Our custom-fit cowl plugs are constructed of marine grade vinyl with an abrasion rating of 250,000 double rubs (ASTM D4157). All our cowl plugs are sewn with bonded nylon thread being one of the strongest threads used today. The cowl plugs are connected by a 36" x 1" black polypropylene webbing. Each set of cowl plugs includes a 12" x 2" bright red safety streamer with bright white eye-catching REMOVE BEFORE FLIGHT text attached for safety. As a secondary precaution each set of cowl plugs will also include (2) 10" long safety flags that get attached to each of the plugs which can easily be seen from the pilot seat. This aids the pilot in removing the plugs from the engine cowling before starting the engine.