Briggs and Stratton Tune Up Kit part# 5109 is for single cylinder engines in the 10.5 Hp to 13.5 Hp range. This kit includes; one-part# 100028 four cycle 48 oz. 30W oil , one-part# 496894S air filter cartridge , one-part# 272403S pre-cleaner , one-part# 802592S spark plug, and one-part# 100002 fuel stablizer . These are all original Briggs and Straton parts and should provide your equipment with the proper pre-season tune up it deserves.