Ref. : FBLS.01BC.36 / FBLS.01BC.37 / FBLS.01BC.38 / FBLS.01BC.39 / FBLS.01BC.40Several models based on the design of FBLS.01. BC.36 exist. The blade is cut in different ways. The spring effect is lateral. The clasp is easy to make but the main fault is that the blade can move inside the box and accidental disengagement is possible. Clasp FBLS.01. BC.39 is an improved model of the same design (FBLS.01 BC.36), but FBLS.01. BC.40 is the safest (a guide installed on the blade prevents any unwanted movement) clasp FBLS.01. BC.38 is with a simplified blade and a revised box (compared to model FBLS.01 BC.32).