Ratio FreeDiver Professional Sapphire RTFvsSeiko 5KX

Ref. ratio-freediver-professional-sapphire-blue-sunray-dial-automatic-rtf0013-500m-mens-watch·MSRP $140
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Measurements
Catalog photos are all shot at the same flattering size. These aren't: every case below shares one millimeter scale.

FreeDiver Professional Sapphire RTF

5KX
Diameter
42mm
42.5mm
Lug-to-Lug
n/a
46mm
Thickness
15.5mm
13.4mm
lowest
Water Resistance
500m
highest
100m
Power Reserve
n/a
41h
MSRP
$140
lowest
$350
Movement
Miyota 8215
Seiko 4R36
Case
5 specsCrystal & Dial
3 specsMovement
3 specsPricing
1 specsReviews
Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.
Owners widely praise the Ratio FreeDiver Professional Sapphire RTF for its exceptional value for money. The watch is noted for its quality construction, with bezels described as having a great feel and minimal back play. One owner highlights an Abyss black dial, sapphire crystal with AR coating, and screw-down crown, built for daily wear with 200m water resistance. On balance, the consensus is that the Ratio FreeDiver Professional Sapphire RTF is a highly recommended watch due to its impressive quality and great price point.
Owners widely praise the Seiko 5KX for its strong lume and value, with many reporting accuracy within +/-5 to 10 seconds per day, though some experience +/-1 second. The 42.5mm case is noted to wear smaller, and the watch offers a comfortable feel for many. Some owners are split on the bracelet quality, with opinions ranging from "cheaper side" with hollow links to "flimsy-feeling" jubilee. A few quality control issues have been reported, including a failed bezel clickspring and misaligned components. The Seiko 5KX is seen by some as a worthy successor to the original SKX, offering an upgraded movement with hacking and hand-winding capabilities, though others lament the loss of ISO certification and a screw-down crown. Overall, owners rate the Seiko 5KX highly for its excellent lume and value proposition, making it a popular choice for everyday wear.
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