User, 18 Oct 2026, asked about the A6-EC400H2B1-M17-STO (400 W, STO, brake, USD 157.91). STO comes only from 400 W; its manual gives no SIL or PL and no certificate, so it cannot replace the contactor; the brake holds nothing on a horizontal axis. Recommendation recorded: keep the 100 W kit; if a rated STO is confirmed in writing, take the brake-less A6-EC400H2A1-M17-STO (USD 129.60) on both axes, 1:2 to 1:3 belt, no contactor.