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Seiko watch · Prospex · automatic

Seiko SRP777 Turtle

The Seiko SRP777 measures 45 mm across, 48 mm lug to lug, and 14 mm thick, with 22 mm lugs. It fits wrists from ~17 cm (flat-fit estimate).

Sources checked · How we source numbers
Case
45 mm1
3 sources disagree; show every value
  • measured 45 mm1
  • measured 44.3 mm2
  • secondary source 44.3 mm3
Lug to lug
48 mm1
2 sources disagree; show every value
  • measured 48 mm1
  • measured 47.25 mm2
Thickness
14 mm1
2 sources disagree; show every value
  • measured 14 mm1
  • measured slightly over 13mm mm1
Lug width
22 mm1
SRP777 Turtle, front view, on wrist
Photo: gabihil, Public domain, via Wikimedia Commons
Seiko SRP777: size drawingSeiko SRP777, cushion case, top and side view to scale: case width 45 mm, lug to lug 48 mm, lug width 22 mm, thickness 14 mm. Bezel, dial and crown size are schematic.lug width 22width 45lug to lug 48TOPthickness 14SIDE
Seiko SRP777, top and side, to scaleDrawing from data, not a photo · mm

Seiko SRP777 specifications

Case diameter
45 mm1measured
3 sources disagree; show every value
  • measured 45 mm1
  • measured 44.3 mm2
  • secondary source 44.3 mm3
Lug to lug
48 mm1measured
2 sources disagree; show every value
  • measured 48 mm1
  • measured 47.25 mm2
Thickness
14 mm1measured
2 sources disagree; show every value
  • measured 14 mm1
  • measured slightly over 13mm mm1
Lug width
22 mm1measured22 mm watches
Crystal
Seiko Hardlex1measured
Water resistance
200 m1measured
Movement
Seiko 4R364seller listing · automaticSeiko 4R36 specs
Battery
none: the Seiko 4R36 is automatic
Years made
20162secondary source
Case code
not in our data yet
Case shape
cushion1measured
Line
Prospex2secondary source
Nickname
Turtle3secondary source

Movement: Seiko 4R36

The Seiko SRP777 runs on the Seiko 4R36, an automatic movement. 47 other models in our base use it.

Beat rate
21,600 bph6
Power reserve
41 h6
2 sources disagree; show every value
  • manufacturer 41 h6
  • secondary source 40, 41 h8
Jewels
246
Accuracy
−35 to +45 s/day7
Hacking seconds
Yes6
Hand winding
Yes6

Battery

none: the Seiko 4R36 is automatic

A mechanical watch has no cell to replace; it needs a service instead.

On your wrist

The verdict compares the lug to lug with the flat top of your wrist. Balanced from ~17 cm, past the edges below ~15 cm.

= 6.7 in

Balanced on a 17 cm wrist: the 48 mm lug to lug covers 88% of an estimated 54.8 mm flat top.

Flat top = circumference ÷ 3.1, a community convention, not a measurement of your arm. Compact ≤ 0.75 of the flat top, balanced ≤ 0.89, at the edge ≤ 1. Compare more watches in the watch size calculator.

Seiko SRP777: wrist fitSeiko SRP777 on a wrist, top view to scale. lug to lug 48 mm. Wrist 170 mm, estimated flat width 54.8 mm (circumference / 3.1). Ratio 0.88: balanced.wrist, flat topwrist flat ≈ 54.8lug to lug 48Balanced · 48 / 54.8 = 0.88estimate: wrist 170 / 3.1 = 54.8 flatcompactbalancededgeoverhang0.750.891
Seiko SRP777 on a 17 cm wristDrawing from data, not a photo · mm

Actual size on your screen

Calibrate once with a bank card and the drawing shows the Seiko SRP777 at 1:1, next to a millimetre ruler.

1:1 · not calibrated: sizes are approximate
Seiko SRP777: size drawingSeiko SRP777, cushion case, top and side view to scale: case width 45 mm, lug to lug 48 mm, lug width 22 mm, thickness 14 mm. Bezel, dial and crown size are schematic.lug width 22width 45lug to lug 48TOPthickness 14SIDE
Drawing from data, not a photo · mm
01020304050

Seiko SRP777 strap size

Lug width 22 mm1measured: a 22 mm strap with 22 mm spring bars fits between the lugs. 45 other models take 22 mm.

Attachment: not published in our sources.

Find your strap length in the watch strap size tool, with the Seiko SRP777 filled in.

On a bracelet? How to remove watch links to size it to your wrist.

22 mm strap: strap diagramTwo-piece strap laid flat (22 mm strap). Lug width 22 mm. Short piece — (unknown), long piece — (unknown). Buckle, keepers and holes are schematic.short —long —lug 22lug 22strap length —22 mm strap
22 mm at the lugs; lengths depend on your wristDrawing from data, not a photo · mm

Same size as the Seiko SRP777

The models nearest to the Seiko SRP777 in case width and lug to lug, drawn over it to scale; below, every model within 1 mm of its 48 mm.

Size comparison: Seiko SRP777, Seiko SRPE03, Seiko SRPE05, Seiko SRPF77Top-view outlines to scale on one centre. A Seiko SRP777: W 45, L2L 48, lug 22, T 14. B Seiko SRPE03: Ø 45, L2L 47.7, lug 22, T 13.2 (vs A: W 0 L2L −0.3 lug 0 T −0.8). C Seiko SRPE05: Ø 45, L2L 47.7, lug 22, T 13.2 (vs A: W 0 L2L −0.3 lug 0 T −0.8). D Seiko SRPF77: Ø 45, L2L 47.7, lug 22, T 13.2 (vs A: W 0 L2L −0.3 lug 0 T −0.8).A W 45B Ø 45C Ø 45D Ø 45B L2L 47.7C L2L 47.7D L2L 47.7A L2L 48A Seiko SRP777W 45 · L2L 48 · lug 22 · T 14B Seiko SRPE03Ø 45 · L2L 47.7 · lug 22 · T 13.2vs A: W 0 L2L −0.3 lug 0 T −0.8C Seiko SRPE05Ø 45 · L2L 47.7 · lug 22 · T 13.2vs A: W 0 L2L −0.3 lug 0 T −0.8D Seiko SRPF77Ø 45 · L2L 47.7 · lug 22 · T 13.2vs A: W 0 L2L −0.3 lug 0 T −0.8
A Seiko SRP777 and the 3 nearest in size, on one centre, to scaleDrawing from data, not a photo · mm

Nearest in size

  1. ASeiko SRP777this watch
  2. BSeiko SRPE03W same · L2L −0.3 · T −0.8 mm
  3. CSeiko SRPE05W same · L2L −0.3 · T −0.8 mm
  4. DSeiko SRPF77W same · L2L −0.3 · T −0.8 mm

Differences against A in mm: W case width, L2L lug to lug, T thickness. Nearest by width and length together, from the published sizes.

Same movement: Seiko 4R36

All 48 models on the Seiko 4R36

Parts documented for the Seiko SRP777

1 claims for named aftermarket parts are in the catalogue. Each claim is tied to this exact model and its seller’s source.

Seiko SRP777 questions

What movement is in the Seiko SRP777?

The Seiko SRP777 runs on the Seiko 4R36, an automatic movement.

How big is the Seiko SRP777?

The Seiko SRP777 measures 45 mm (44.3 mm measured) across, 48 mm (47.25 mm measured) lug to lug, 14 mm (slightly over 13mm mm measured) thick.

Will the Seiko SRP777 fit a 7-inch wrist?

Balanced: the Seiko SRP777's 48 mm lug to lug takes 84% of the ~57.4 mm flat top of a 7-inch (17.8 cm) wrist. By the same estimate (circumference ÷ 3.1) it sits balanced from about 17 cm and overhangs the flat top on wrists under about 15 cm.

Does the Seiko SRP777 need a battery?

No. The Seiko SRP777 has no cell to replace: a wound mainspring drives its automatic Seiko 4R36.

What strap size does the Seiko SRP777 take?

The Seiko SRP777 measures 22 mm between the lugs, so it takes a 22 mm strap with 22 mm spring bars. 45 other models in our base share that width.

Find the strap length for your wrist and the Seiko SRP777 in the watch strap size tool.

More Seiko watches

Sources

Documents checked · Report a wrong number

  1. 1WatchClicker — Seiko Turtle SRP777 Review - compared to SKX007 · html · read
  2. 2Exquisite Timepieces — Seiko SRP777 vs SRPE93: Which is the Superior Turtle? · html · read
  3. 3StrapsCo — Seiko Lug Widths & Strap Sizes (reference table) · html · read
  4. 4Watchoutz — Seiko Prospex Mechanical Automatic Diver's 200M Turtle SRP777 (product page) · html · read
  5. 5Belmont Watches — Seiko Prospex Diver Turtle SRP777 (pre-owned listing) · html · read
  6. 6Seiko Watch Corporation — Instructions: Seiko Automatic Diver's Watch Cal. 4R15/4R16/4R35/4R36/7S26/7S35/7S36 (English) · pdf · read
  7. 7Seiko Watch Corporation — Instructions: Diver's Watch for Air Diving, Cal. 4R35 / 4R36 (English) · pdf · read
  8. 8Grail Watch — Grail Watch Reference: Seiko Cal. 4R36 · html · read
  9. 9Seiko Watch Corporation — Instructions: Mechanical watch, Cal. 4R35 / 4R36 / 4R37 / 4R38 / 4R71 / 4R72 / 4R39 (English) · pdf · read