Swaziland 1937 Rare KGVI Registration Envelope Die Proof

1937 DIE PROOF for KGVI 4d registration envelope duty: Superb embossed proof in red on wove paper initialled and dated "1/10/37". Marked "V742". Extraordinarily fresh, most attractive. A rare archival piece being one of only 2 such proofs extant. Ex De La Rue Archives.