Rob Allen has been working with latex tubing for spearguns for years. Testing and retesting until he found the right manufacturer and mix to ensure his guns have the best, most consistent bands, to ensure accuracy over 100s of shots. Rob's focus was on offering a latex band that could maintain its tension for as long as possible. The focus for Rob was to have a rubber that could be cut to peak performance, (say 60kg tension) when loaded, but only loose a couple KG of tension after an extended period (say 40min). This is important in maintaining accuracy and speed. It's what makes the difference between Rob Allen blue rubber and cheaper brands. Many other bands will load up to a peak tension of say 60kg but then within 5-10min will drop back down to 44-46kg, so they are losing large amounts of power over a short time, thus affecting spear trajectory, accuracy and speed. The key is consistent quality of the raw material latex and the manufacturing technique and environment. Rob Allen rubber is a laminated pure latex core with a UV resistant outer blue layer. Robs blue rubber is available in 14mm, 16mm, 18mm and 20mm so you can fine-tune the power and delivery for your guns needs.