Review on Waterproof Bike Seat Bag by ROCKBROS, 3D Shell Saddle Bag for Mountain and Road Bikes - Cycling Seat Pack Under Seat by Santiago Serrano

I was looking for a small bike backpack to replace my previous backpack which was small enough to only fit my phone (barely stretched) and keys or wallet and keys - but not all three. And I didn't want anything bulky. This backpack is very suitable for the purpose I need it for. the bike seat of my Giant Contend bike. It's easy to put on and the stiff sidewalls are a real plus.