missing rear sight blade

I recently purchased a Detonics CombatMaster MK VI in perfect condition except of course the blade is missing from the rear sight. Does anyone know what blades might be used in this sight. I don't know who manufactured the Detonics sights. I've even thought about modifying a piece of hacksaw blade into a notched blade to fit it. I just don't want to replace the whole rear sight if I don't have to.