The O.S. Nº8 glow plug is the most widely used O.S. glow plug. Recommended for most current O.S. (and other brands of) 2-stroke R/C engines. FEATURES: -Medium heat range plug for most model engine applications. - Plug is medium length, without idle bar. For all 2 stroke engines. INCLUDES: One glow plug and one brass washer SPECS: Threads on the plug are 1/4-32.