SDG Tellis Dropper Seatpost - 34.9mm 125mm BlackSDG Tellis Dropper Seatpost 34. 9mm 125mm Black. The Tellis is one of the most durable and simplistic droppers on the market with an easy cable actuated sealed hydraulic cartridge system featuring the softest lever action in the game and backed with a 2 year warranty and global support services all at an affordable price point that doesnt break the bank. Internal routed infinitely adjustable design Simplistic fully sealed alloy cage stainless tip