This is a very early - 1925 or early 1926 - Mullard PM series box. The boxes were made in various colours. Note that this one lacks any mention of the BVA and has a short list of patents above the thinker.
This is a very early - 1925 or early 1926 - Mullard PM series box. The boxes were made in various colours. Note that this one lacks any mention of the BVA and has a short list of patents above the thinker.