02-19 HONDA CRF450R: Pro Taper Twister Throttle Tube Pro Taper&#39;s Twister throttle tube is constructed from quality anodized billet aluminum. The sealed radial ball bearing and polymer bushing allow for a consistent and smooth throttle operation while a knurled grip mounting area ensures a vice-like grip bond. The Pro Taper Twister Throttle tubes are used by top-level pro teams and riders worldwide. Twister Throttle Tubes are compatible with all Pro Taper handlebars and Renthal 7/8" handlebars with the standard bearing insert. Precision CNC machined.