Serfas LT-4 Bag

When fully expanded, the Serfas LT-4 provides 105 cubic inches of storage space. This is generally enough to fit a spare tube, tire levers, a multi-tool, and a CO2 inflator or small patch kit.

Yes, the bag uses a dual-attachment system that secures to both the saddle rails and the seat post. This creates a stable, rattle-free fit that keeps your gear from shifting during bumpy rides.

The LT-4 is designed with a compact, aerodynamic profile that fits most standard bicycle saddles. While it is highly compatible with traditional rail setups, it may not fit on some specialized aero posts or saddles with extremely limited rail clearance.

The bag features a simple zippered expansion gusset. When you need extra room, you unzip the perimeter to increase the bag's depth from 4 inches to 5 inches, allowing for a bit more bulk without needing a larger bag.

The bag includes reflective logos and piping designed to catch ambient light from headlights. While they significantly improve your visibility to drivers from the rear, they should be used as a supplement to, not a replacement for, active rear bike lights.