a quartz watch, 36-40mm and fairly slim, must have date, fairly robust reasonable level of waterproofness.
Of the CWC watches, the CWC GS Sapphire Stainless Steel has a screw-down crown and 200m WR, but it is not in stock.
From Timefactors, the similar Precista G10 Military PRS-10 Sapphire has a screw-down crown and 100m WR. The crystal shape is domed which differs from the CWC Sapphire. Also from there, and larger at 40mm diameter, is the Smiths 'Seafire' with no screw-down crown but 100m WR, which has an unusual 4-ticks-per-second quartz second hand giving a more continuous sweep. [edit: Seafire is not exactly slim].
Of the CWC watches, the CWC GS Sapphire Stainless Steel has a screw-down crown and 200m WR, but it is not in stock.
From Timefactors, the similar Precista G10 Military PRS-10 Sapphire has a screw-down crown and 100m WR. The crystal shape is domed which differs from the CWC Sapphire. Also from there, and larger at 40mm diameter, is the Smiths 'Seafire' with no screw-down crown but 100m WR, which has an unusual 4-ticks-per-second quartz second hand giving a more continuous sweep. [edit: Seafire is not exactly slim].