The thermal-magnetic TM-D trip gives you an instantaneous magnetic trip for short-circuits and a thermal bimetal for overloads; no electronic adjustment, so it's a fixed-curve device suited for straightforward distribution or feeder protection where you don't need field-adjustable settings. Mechanical durability of 20,000 cycles and electrical durability of 20,000 cycles at 440 V In/2 (half rated current) or 10,000 cycles at full rated current — that's the life you get before the contacts wear out. For a distribution breaker that operates maybe a few times a year, that's effectively the life of the panel. For a frequent-switching application like a motor disconnect, you'd want a contactor instead.
The 108 mm width, 137 mm height, and 80 mm depth fit a standard 12-module 9 mm pitch DIN-rail footprint. The 35 mm connection pitch with spreaders (27 mm without) tells you the busbar hole spacing you need.