I purchased this heavy duty bag to use on my Honda Goldwing motorcycle. I have now used the bag a dozen times on trips of 150 to 300 miles each. Three of the trips where in the rain and of those, two in heavy rain while I was on the NYS Thruway, Interstate 84/86. I ride in all weather except road covering snow. The bag is easy to pack and has a semi-ridged bottom with drain holes. The drain holes are just for the bottom protective panel that is attached/welded to the main bag. The material is  flexible fiber re-enforced vinyl thick enough so as to not flap in the wind. There is a carry handle and shoulder strap that provide secure points for me to secure the bag to my rear luggage rack with my luggage straps. The bag closes by squeezing the Velcro seal together at the mouth of the bag then rolling the excess top of the bag on the semi-ridged strip that is also on the mouth of the bag. The top is then rolled down to custom fit the contents then secured with 4 adjustable snap buckles, 2 in the middle and 1 on each end. Most important my clothes stay dry and dust free. I am very happy with the bag and had a riding buddy purchase a bag for use on his BMW bike. Heat does build up quickly in the bag when riding in the sun but that is so with any sealed bag. So next time I will but the chocolate bar in my side bag. That said the bag was easy to clean with a garden hose.