1. (a) Two inch nominal thickness hardwood, covered on the exterior with a minimum of No. 20 Manufacturers Standard Gage Steel, or,
2. (b) Two thicknesses of 1 inch thick plywood, covered on the exterior with a minimum of No. 20 Manufacturers Standard Gage Steel, or,
3. (c) Fiber, equal in strength to the wood as specified in Sections 1578.1(a) and 1578.1(b), covered on the exterior with a minimum of No. 20 Manufacturers Standard Gage Steel, or,

4. (d) A minimum of No. 14 Manufacturers Standard Gage Steel, lined on the interior with 1 layer of 1 inch thick plywood, or equivalent material.

   All corners of Class II magazines shall be provided with substantial bracing or shall be of rabbeted joint construction. The interior shall have a smooth finish without cracks or crevices with all nails, screws, bolts and nuts countersunk. Exposed metal shall be covered so as not to come into contact with packages of explosives.

Class II magazines shall be constructed as follows: