fire both the stylet 20 and the cannula 14 the indicator 53 shows green a molded piece part comprising the housing 12 is illustrated in perspective in fig3 molded from a suitable medical grade plastic in an injection molding operation the housing 12 includes a generally flat base 54 having a slot 56 formed longitudinally through it supported on the base are first and second generally tubular portions 58 and 60 with a common wall 62 extending between them formed through the thickness dimension of the tubular member 60 is a longitudinally extending slot 64 leading away from a generally rectangular aperture 66 likewise the tubular member 58 also includes a longitudinally extending slot 68 the wall 62 where the tubular members 58 and 60 merge with one another define a v shaped groove 70 integrally formed with and projecting upwardly from the top surface of the tubular members 58 and 60 are wedge shaped wings 72 and 74 whose vertical walls 76 and 78 define a guideway for the stylet gripper member 22 that is the stylet gripper member 22 is dimensioned to fit between the vertical walls 76 and 78 and with the fin 42 resting in the v shaped groove 70 referring next to fig4 there is shown a stylet spring retention sleeve 47 which is generally cylindrical and which has the match member 46 integrally molded therewith the sleeve 80 has a generally open rearward end 82 and a closed forward end 84 the closed end 84 includes a rectangular aperture 86 the outside diameter of the sleeve 82 is sized so as to allow it to freely slip into.