This rim is built specifically for the rigorous demand a unicycle puts on a rim. Its the same rim as the double walled eyeletted alloy rim used on the Nimbus 29" Mountain and Road Unicycle.
Should you want to build the wheel, here is a link to the spoke calculator so you can find the correct spoke length you need.
Width Outside: 42mm
Width Inside: 32mm
Spoke Holes: 36
Material: High Quality 6061 heat treated aluminum with box section
Finish: Black anodized
Nipple Eyelets: Stainless Steel