Sacom 60AC358 Drain Plug

Water drain plug for a Sacom 60AC358 Air Conditioner.

The model has two grooves to fit o-rings. One is in the middle of the inner part of the model and the second one is at the bottom on the inside.
If you don´t have o-rings in the right size you can try pushing a ring of butyl-cord down in the middle and screw on the plug. This will push it all the way to the bottom to form a makeshift o-ring.