Unimatic Modello Quattro UC4 Classic Time OnlyvsYema Diver

The Unimatic Modello Quattro UC4 Classic Time Only features a robust 40mm black DLC case, 13.7mm to 13.9mm thick, with drilled lugs and a fixed steel bezel that balances beefiness with wearability. Reviewers note improved crown action and refinement over earlier models, with a flat sapphire crystal. Its sandwich dial reveals Super-LumiNova BG W9 beneath cut-out indexes, paired with a Seiko NH35A automatic movement. While the movement is considered robust and reliable, one reviewer expressed a preference for a Sellita caliber given the watch's heft. On balance, reviewers find the Unimatic Modello Quattro UC4 Classic Time Only to be a well-refined and wearable tool watch with a distinct military character.

One owner reported a water ingress issue on their Yema Diver the first time it got wet in a lake, despite rinsing and inspecting the watch and bezel. Another owner notes this manual wind Yema Diver has a cool patina but is unlikely to be waterproof or gain value. Overall, owners view the Yema Diver as a fun second watch rather than an investment.