Rock Shox Crown/Steerer/Upper Parts. Features: Tapered steerers (when offered) are designated by 1.5>1-1/8" spec info Replacement CSU (crown/steerer/upper) units and BoXXer crowns BoXXer top crown sizing reference (head tube+headset): short (3/4" drop): under 160mm/tall (2" drop): 160-190mm *Totem and Lyrik CSU assemblies are from SoloAir fork model (will work with 2-StepAir, DualPositionAir (2P-Air) and U-Turn/Coil models, but will not have travel gradients on stanchion) 2013-15 Reba and SID-B SoloAir CSU assemblies are not compatible with DualAir 2008-2013 SID-A CSU assemblies are for DualAir only (2009 and older fork parts are no longer available if not listed) Specs: Model:2019+ BoXXer (C1) Description:taper-wall aluminum stanchion tube, black (right)