Bushwhacker Tacoma - Bicycle Expandable Seat Bag - w/ Reflective Trim & Light Clip Attachment - Cycling Under Seat Wedge Bike Rear Saddle Pack Frame Front Accessories Wide mouth opening for easy access. Reflective Trim and light clip attachment for increased visibility. Attaches under seat with two quick secure straps. Stiff inner shell maintains its shape. Expands for increased capacity. Dimensions: 8.5" L x 5" W x 5" H Expanded: 8.5" L x 5" W x 9" H