trailed with the FN knife bayonet the X2E1, Other versions of trials blades used a double sided blade similar to the Belgian FN49, and the X2E1 without the flash hider prongs (X3E1). The No5 was used as the basis of the L1Ax series of blades. The trials version of this blade was the X4E1, this is similar to the production versions but without any markings