# BlueRobotics Tether Thimble Diameter **URL:** \ **Category:** Blue Robotics Products\ **Created:** [July 22, 2024, 8:41pm UTC](https://discuss.bluerobotics.com/t/bluerobotics-tether-thimble-diameter/17509 "2024-07-22T20:41:03Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![3dMB](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/3dmb/32/13905_2.png) [@3dMB](https://discuss.bluerobotics.com/u/3dMB)\ **Post date:** [July 22, 2024, 8:41pm UTC](https://discuss.bluerobotics.com/t/bluerobotics-tether-thimble-diameter/17509/1 "2024-07-22T20:41:03Z")
I see that the 4UTP [Fathom Tether](https://bluerobotics.com/store/cables-connectors/cables/fathom-rov-tether-rov-ready/) specs show a minimum working bend diameter of 75mm (just shy of 3" for those across the pond), however the [Thether Cable Thimble](https://bluerobotics.com/store/cables-connectors/tether-management/fathom-p-thimble-r1/) with a hole of 25.4mm (1") has a working diameter of around 40mm (or around 1 1/2") - I have not measured exactly. Either way, this would be around half of the bend diameter specified on the cable specs. Any idea why and does this mean that using the supplied thimble will reduce the life of the tether? ---
**Author:** ![tony-white](https://sea1.discourse-cdn.com/flex019/user_avatar/discuss.bluerobotics.com/tony-white/32/18385_2.png) [@tony-white](https://discuss.bluerobotics.com/u/tony-white)\ **Post date:** [July 29, 2024, 8:00pm UTC](https://discuss.bluerobotics.com/t/bluerobotics-tether-thimble-diameter/17509/2 "2024-07-29T20:00:07Z")
Hi @3dMB - The bend radius is indeed larger than what is used on the thimble, however since the thimble holds the tether in a fixed orientation, no reduction of life would be expected. We may need to update our technical specifications to reduce the allowed bending radius, as 75mm is likely higher than it needs to be!