recess 160 a facilitates releasable engagement of the anvil assembly 100 to the stapling device 12 referring also to fig6 the collet 150 may be substantially rigid and is positioned within the longitudinal bore 122 defined by the anvil shaft 104 the collet 150 is substantially cylindrical and defines a longitudinal bore 152 fig7 that is dimensioned to receive the trocar 22 fig1 a distal portion 154 of the collet 150 includes a plurality of cantilevered fingers 156 each of the fingers 156 includes a protrusion 158 that is dimensioned and configured to be received in a respective one of the holes 136 fig5 formed in the anvil shaft 104 as described in further detail below referring to fig7 9 in order to assemble the collet 150 within the anvil shaft 104 the distal end of the collet 150 is inserted into the proximal end of the longitudinal bore 122 of the anvil shaft 104 and slid distally in the direction indicated by arrow u201c a u201d in fig7 and 8 the collet 150 is positioned to align the protrusions 158 with the longitudinal channels 134 positioned between the flexible legs 120 when the protrusions 158 engage an inner wall of the flexible legs 120 the fingers 156 are deflected inwardly in the direction indicated by arrow.