All sizes and length are approximate:

The Medium Bag measures approximately 8" across bottom, 5" wide and 10" high. The strap lengths are; Short 14", Medium 22.5" and Long 24" measuring from the bottom of the bag to top of the extended straps.

The Large Bag measures approximately 11" across bottom, 5" wide and 11" high. The strap length is 24” measured from the bottom of bag to top of extended straps.

 The Extra Large Bag measures approximately 14" across bottom, 5" wide and 13" high. The strap length is 26"  measuring from bottom of bag to top of the extended straps.

The bag has  (four) 4 outside pockets for Water Bottles, Cell Phones, Keys, Brochures, Pictures, Mail, ect..

The Medium Bags outside center pocket measures approximately 3.5" X 5" X 7" deep, the Large Bag outside pocket measures approximately 6.5" X 5" X 8" deep,and the Extra Large Bag outside pocket measures approximately 9.5" X 5" X 10" deep. The pockets on the side, in all size bags, are approximately 2" X 5". There is a zipper across the top of the bag for security.