Bushwhacker&reg; Mesa Trunk Bag Black - w/ Rear Light Clip Attachment & Reflective Trim - Bicycle Trunk Bag Cycling Rack Pack Bike Rear Bag Made with durable 600 denier polyester fabric. Fully padded, insulated interior. Rear light clip attachment and reflective trim for visibility. 4 point velcro mounting system for easy, secure attachment Dimensions - Main Compartment: 12" L x 6"W x 7"H. Side Pockets: 10.5" L x 2" W x 5" H.