The 1+N-pole design switches both line and neutral, with the neutral pole switching but not protecting — a common arrangement for single-phase final circuits where you want isolation on both conductors.
The C-curve means the magnetic trip fires at 5 to 10 times rated current (50–100 A for this 10 A unit). That suits loads with moderate inrush — think lighting banks, small motorized appliances, or general socket outlets — where a B-curve would nuisance-trip on startup but a D-curve would let a hard fault run too long. The 70 mm installation depth matches standard SENTRON 5SY series enclosures and DIN-rail distribution boards.