This is the O.S. Max Two-Stroke 1.20AX Ringed Engine without Muffler.

Model Application: Ideal for 3D, Precision and Sport flying
Mounting Application: Mounts in same space as the .91FX (actual
mounting dimensions vary slightly, see SPECS)
Construction: Steel piston ring and liner, aluminum piston
Carburetor: 70D with rearward angled needle valve for safety
Glowplug: O.S. #8 supplied with engine, A5 will also work
Warranty: Two-year limited

O.S. Max Two-Stroke 1.20AX Ringed Engine with #8 glow plug, prop
washer and nut, needle valve extension set, instruction manual
and decal set

Fuel: Two-Stroke with 18% lubricant and 5-20% nitromethane
Muffler: E-5020 "Power Box"
Propeller: 15x10-12 or 16x8-10
Field Equipment: Glow starter, fuel filter, fuel pump, fuel tubing

Displacement: 1.218 cu in (19.96cc)
Bore: 1.197" (30.4mm)
Stroke: 1.083" (27.5mm)
Crankshaft thread size: 5/16-24
Practical RPM: 1,800 - 9,500 RPM
Power Output: 3.1ps/9000 RPM
Weight: 22.82oz (647g) without muffler
7.074oz (219.2g) with 90° adapter installed
7.907oz (245g) with extension installed

Distance Between Mounting Holes Same Side: 0.98" (25mm)
Distance Between Mounting Holes Opposite Side: 2.3" (58mm)
Distance Center of Crankcase to End of Crankshaft: 4.3" (109.5mm)
Distance Center of Crankcase to Drive Hub: 2.7" (69.8mm)
Width Between Mounting Tabs: 2.6" (67mm)
Width of Crankcase Below Mounting Tabs: 1.8" (46.5)
Length from Backplate to End of Crankshaft: 5.5" (139.9mm)
Length from Backplate to Drive Hub: 3.9" (100.2mm)
Height/Bottom of Crankcase to Top of Cylinder Head: 4.3" (109.2mm)
Height/Bottom of Mounting Tabs/Top of Cylinder Head: 3.4" (85.7mm)

Needle Settings: High Speed: 2 - 2.5 turns out from fully closed
Low Speed: 3/4 turn out from fully closed with the
throttle fully closed