KOSPET Tank T4 vs M4

The M4 SE is the better daily wear: a 1.96-inch AMOLED versus 1.43, and multi-band GPS, which actually locks faster and holds signal under tree cover or between buildings where the T4's 6-satellite fix drifts. For route tracking that matters. The T4's answer is water: 10ATM rated depth beats the M4's IP69K (which is about pressure jets and dust, not as deep a swim). It is also the more compact body, so it sits under a sleeve. Both keep offline maps, both run roughly a day of heavy use on ~470-480 mAh. If your activity is swimming or you want the smaller watch, the T4; if you want the screen you can read in sun and GPS you trust off-road, the M4 SE.

Take the KOSPET Tank T4 if you swim or dive and prefer a compact case. Take the Tank M4 SE if GPS accuracy and a readable screen matter more than extreme depth, which for most land users they do. At identical price the M4 SE is the more modern pick.