It’s a Velo saddle, like KH with same lift handle and rear bumper. It’s buy it now for $24.99. Same basic seat but a lot less than UDC.
http://cgi.ebay.com/VELO-Replacement-UNICYCLE-Saddle-NEW-Seat_W0QQitemZ7235327922QQcategoryZ22693QQrdZ1QQcmdZViewItem