For Shimano I spec compatible brake levers. Dropper post lever.
Mountain Cycling Dropper Post - Height Adjustable Seatpost, Dropper Post Lever Controller for Adjustment, Adjustable Control Seatpost with Shifter, Cycling Accessory for , Remote Lever Performance
DJC Bike Dropper Seatpost Jump Seat Post 100mm Travel Manual Control Lever Height Adjustable Seatpost Hydraulic 375mm (30.9mm Diameter)
XUJINGJIE Mountain Bike Dropper Seatpost Aluminum Alloy Bicycle Seat Post Hydraulic Lifting Remote Control Adjustable Seatpost Tube, 27.2mm/31.6mm,27.2mm
Hydraulic Dropper Seatpost for Bicycle, 125mm Travel Hydraulic Adjustable Seatpost 27.2-33.9mm, Oil-Gas Locking System(31.6mm)
Hydraulic Dropper Seatpost for Bicycle, 125mm Travel Hydraulic Adjustable Seatpost 27.2-33.9mm, Oil-Gas Locking System(30.9mm)
MTB Bike Seatpost Hydraulic Seat Post Bicycle Dropper Adjustable 30.9mm / 31.6mm
