The Tost Aero 200x50 inner tube (also referenced as 7x1 3/4) is an aviation-grade rubber tube designed for use with 200x50 aircraft tires on gliders and light aircraft tailwheel systems. It is built for high reliability in aviation ground operations, where consistent pressure retention and durability are critical.

This specific variant features a bent valve configuration for easier inflation access in tight wheel assemblies, commonly used in sailplanes and tailwheel setups.

Its primary features include:
Aircraft-grade inner tube for 200x50 (7x1 3/4) tires
Compatible with Tost Aero glider and tailwheel systems
Valve options: 90°/90° or 90°/30° angled Schrader valve
Designed for 3.5" wheel hubs used on gliders
Durable natural rubber construction for aviation use
Good air retention and resistance to deformation
Suitable for grass strip and training field operations
Matched specifically to Tost aviation tires for optimal fit

The two main valve configurations typically available are:

90°/30° valve (more common for one-piece wheels) 
90°/90° valve (used for multi-piece hubs like Max II systems) 
This tube is widely used in gliding operations because it is designed specifically for aviation tire flex cycles and is more reliable than generic industrial or bicycle tubes when exposed to repeated takeoffs, landings, and low-pressure operation.

In short: it is the dedicated aviation inner tube for 200x50 Tost tailwheel and glider wheel systems, with a 90° angled valve option for easier servicing in confined wheel assemblies.