Fidlock Twist Spare Bottle - Transparent Black - With Connector On Bottle - 590ml NoAusPost they have centre marking and

they have centre marking and length markings so you can cut them down with precision

Diameter - 25-26mm outer diameter

Cons: There are cheaper options that do the same thing

It features an anatomic race-inspired low profile

Fidlock Twist Spare Bottle - Transparent Black - With Connector On Bottle - 590ml NoAusPost they have centre marking andThe exchange is simple: open the connectors locking with a coin, attach it to the new replacement bottle, close the locking cheers! Upgrading to the new TWIST bottle with the new lid, easy squeeze material and reworked overmolding technology is super simple. The replacement bottle is compatible with the connector of your old bottle. Features New leak proof, self sealing bottle cap with a high water flow valve and optional dirt cover Dishwasher safe