Sandwich assemblies of natural rubber and specially blended synthetic compound bonded to two metal plates. Proper installation requires that the space be designed to the correct length to precompress each mounting to guarantee proper positioning of the mountings. Set consists of eight bonded sandwich mountings, four 4130 steel spacers with mounted rubber shoulder. Use with dynafocal engine mount rings using 2-3/4″ I.D. retainer cups. Heavy duty designed for use on aerobatic aircraft. Same style as homebuilt type but inner cone has been strengthened and elastomers added to encapsulate the spacer. EM100-005 for use with engines rated up to 200 HP.