I'm into Marsee bags. Use a 11 litre" Rocket Pocket" expandable tank bag, with a four quick release strap base. Also use a magnetic base 15 litre "Ovalution" tank bag with it's base pad hook and looped to the seat, use a Rokstrap to secure it. Just unzip both from their bases and go. Can't get new ones, anymore. Have purchased 7 of them over the last two years from California mainly. Also have Kreiga 10 litre and 20 litre US bags. But using them everyday is not as convenient as top zip bags. Both are top quality kit, Kreigas are waterproof. Usually pay $50 to 70 for the Marsee tank bags. Three of them, were good as new.