The Almsthre Top Tube Bag mounts between your stem and saddle using either velcro straps or direct bolt-on hardware. The bag includes trim-to-length velcro straps that wrap around your top tube and head tube, plus two bolts for frames with 63-millimeter bolt spacing on the top tube. A head tube tether cord prevents the bag from sliding backward when you brake or climb steep grades. The dual mounting options work whether you ride a traditional frame without mounting points or a modern gravel or bikepacking frame with integrated bosses.

The bag measures eight inches long by two inches wide by three and a half inches tall, which holds 0.8 liters. That capacity fits a phone, energy gels, a spare tube, tire levers, a compact pump, and keys without creating bulk that interferes with your knees during pedaling. The single central zipper runs the length of the top panel, providing full access to the interior without requiring you to reach around sides or corners. A cord access port on the front panel routes charging cables or headphone wires through the bag, keeping them organized and preventing snags on brake cables or frame tubes.

Silicone grippers line the bottom of the bag where it contacts your top tube. These grippers prevent the bag from shifting side to side or rotating during rough descents or when you lift your bike. The ripstop nylon construction with a waterproof zipper keeps contents dry during rain and protects against punctures from sharp items inside the bag. The material cleans easily after muddy rides, and the construction handles regular use without wear showing at stress points where the straps attach.