Keyway size is 1/4" x 1/8"

1 3/16 square

3165 Continental gas

375 Disk - 690

Holes are pre-set and drilled

Custer HF18A-PHD 18 LED Magnetic Amber Flasher A-43V1221 Keyway size is 1/4" xKeep yourself visible and safe on the road with this heavy duty Magnetic LED Safety Light. Amber Safety Light is so bright it can be seen for more than one mile making it ideal for marking trailers, vehicles and implements. 18 highly visible, super bright LEDs that can be seen up to 1 mile away Battery Operated Takes 4 AA Batteries Lights can be set to flashing or steady All weather resistant Approximate size 6" wide by 4" high Will flash for up to 72