Positioned for minimum wind resistance and easy access. These bags are ideal for triathletes or riders wanting to keep energy food or other small items close at hand. The Tri Bag by Topeak offers three different models to choose from: mesh cover, rain cover, or fully waterproof DryBag. The Tri Bag features internal compartments to keep your items separated and organized. It is easily attached to your bike frame or rack with a simple velcro strap fixing. The sizes and capacities available are as follows:- Mesh Cover: - Small: 14x4x10.2cm, 0.6L, 59g - Large: 18x10.2x4cm, 0.72L, 72g- All-Weather: - Small: 14x4x10.2cm, 0.6L, 65g - Large: 18x10.2x4cm, 0.72L, 80g- DryBag: - Small: 14.5x4.7x12.8cm, 0.6L, 65g - Large: 18x12.8x4.7cm, 0.72L, 120gPlease note that sand, dirt, mud, etc., and bags that are incorrectly packed may cause the bike frame paint to become dull or scratched over time. To avoid any potential damage, it is recommended to protect the frame or rack with foam covering or protective film before attaching the bags or panniers.