From the publisher:
These super-sized 25mm 6-siders are Warehouse 23 exclusives, and they glow in the dark! The set includes two jumbo dice -- a "Munchkin d6" and a "Monster d6," with classic John Kovalic art on every face.
Similar to the standard Munchkin Jumbo D6, but with a whitish color that glows in the dark. Also, no cards are included with this version. Released in April 2011, a couple months prior to the other Jumbo d6s. Only available from the publisher's online store.
While no cards come with these dice, the publisher released a promo card called Ghost Hands, that specifically requires the glow-in-the-dark Jumbo d6 dice.