Start with your everyday load
Lay out what you normally take: rain layers, small personal items and anything you need at your destination. Compare the shape and usable space of the bag, as well as its listed capacity.
Choose the mounting position
A tank bag keeps small items nearby. A tail bag uses passenger-seat or rack space. A top case needs a compatible support system. Check fuel-cap access, seat removal and clearance around the rear of the bike.
Look at the whole attachment system
Confirm straps, bases and mounting hardware for the exact option. A modular luggage image can show several components even when only one component is selected.
Ask about the exact weather-protection version
Roll-top construction, fabric, seams and closure details all matter. Some product families include both standard and weather-protected variants. Ask for the specific version and care instructions before ordering.