I have a model 313.54406 Sears torch handle and a model 313.54408 Sears cutting torch. It was really made by Harris. Does anyone know the corresponding Harris model numbers?

I'm asking because the the o-rings on both the welding and on the cutting torch pieces need to be replaced. With the Harris model numbers, I could order new ones.

I can probably figure out the sizes even without the Harris model number, but what should the o-rings be made from? What materials are safe with acetylene & oxygen?