Designed specifically for purpose, beveled backs less than 2mm thick. Guaranteed not to rub, will not move or come off accidentally. Stop numbers flapping. Re-usable becomes part of your kit, no more safety pin failure. Lightweight – less than 1gsm – 25mm x 20mm. Works on most Sports Materials**. For Running, Cycling, Triathlons
** With the development of modern materials, we strongly recommend testing on a small unimportant area of your garment.