Pololu ball caster kits with spacers and screw sets pololu 955 this ball caster kit has a 34in diameter metal ball the kit includes a black abs housing a 34in diameter metal ball two 116in spacers and two 2 screw sets the total height of the ball caster 083in can be increased by using the included spacers to approx 1in this ball caster is just one of the many pololu accessories carried by rapid for further resources please see here pololu 955 ball caster 34 inch includes tw