Rask

Kastaplast says this about the Rask:

A CONCEPT DISC BASED ON KASTAPLAST’S INVENTION FOR DRAG REDUCTION. BEING SUPER FAST AND VERY OVERSTABLE, THE RASK SHOULD PROBABLY HAVE A WARNING STICKER ON IT.
Being less than 22 mm wide at the rim, Rask proves that a disc’s speed cannot be determined by looking at the width of the rim. Those who want the fastest disc available, without the widest rim, reach for Rask! Some players swear by it, but it sure isn’t for everyone. Rask is Swedish for fast.