Works with all 1/10 & 1/8 scale Redcat Racing Nitro Models
This works with Vertex .16 and .18, and SH .18 and .21 nitro engines
Does not work with O.S. .21 engine included with Earthquake 3.5 for a few years(Black Head), if your Earthquake 3.5 has a blue heatsink head then this is compatible.