Addiesdive Tuna 300M Automatic Dive Watch AD2509vsLongines HYDROCONQUEST
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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.

Tuna 300M Automatic Dive Watch AD2509

HYDROCONQUEST
Diameter
41mm
43mm
Lug-to-Lug
44.5mm
lowest
53.5mm
Thickness
15mm
11.9mm
lowest
Water Resistance
300m
300m
Power Reserve
n/a
72h
MSRP
$139
lowest
$2,000
Movement
Seiko NH35
Longines L888
Case
4 specsCrystal & Dial
1 specsMovement
2 specsPricing
1 specsReviews
Synthesized for each watch independently from owner discussions, enthusiast forums, written reviews, and video reviewers.
Owners widely praise the Addiesdive Tuna 300M Automatic Dive Watch AD2509 for its excellent value, with many finding the case finishing comparable to higher-priced brands and appreciating the sapphire crystal and strong lume. The Seiko NH35 movement is generally considered reliable and keeps good time, with some owners reporting accuracy within +1/+2 seconds per day, while others note figures around -6 seconds per day. The watch is seen as a competent homage, featuring a ceramic bezel insert and solid link bracelet. One owner noted the 39mm case size as easy to wear on a 7-inch wrist. However, some owners express skepticism regarding the actual water resistance beyond casual use, despite the 300m rating, and question the warranty's reliability. The bracelet is frequently described as significantly worse than that found on comparable brands, though still visually appealing. Quality control variance is a concern for some, with instances of misaligned bezel inserts reported.
Owners widely praise the Longines HYDROCONQUEST for its attractive sunburst dials and near COSC accuracy, with one owner noting a movement losing only about 2 seconds per day. However, opinions are divided on the bracelet, with some finding it comfortable and featuring a useful slide-lock extension, while others criticize it for lacking micro-adjustments, having pinch-prone links, sharp lugs, and an uncomfortable feel. The screw-down crown operation is also a point of contention, described by some as inconvenient or difficult. On balance, owners rate the Longines HYDROCONQUEST highly for its striking dial and value, despite mixed views on its bracelet and crown usability.
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