We don’t have anything made specifically for the U87 for outdoor use.
The closest we have would be the Windjammer fur we make for the Neumann TLM 103:
Description: Neumann TLM 103 MiniWindjammer
Order Code: 055456
Web link: www.rycote.com/products/055456
The diameter for the TLM 103 is 60mm. The diameter for the U87 is 56mm. Therefore is should fit fine!