A sample from the products for the Gasket Kit B include: Oring 183, Gasket,mission Co (mca), Washer 7.2x13x1.2, Gasket Kit B.
With a quantity of two pieces, the O-ring 46.4x1.9 is the most used part in the GASKET KIT B diagram.
The most reasonably priced component used on the Cn250 Helix 1986 (g) Canada / Kph Gasket Kit B is the Washer, 10.2m/m.