Because..... he's under Bonny sponsorship, but wearing Yonex gear. In the video above, Wei Nan is wearing the SHB-01LCW Lime/Orange, and as far as I can tell, at Singapore Open at least, the racquet he's using is the Z-Force 2. Wei Nan has been wearing SHB-01LTD purple and 01LCW dark pink as well. Feels as if Bonny has nothing proper enough to field him for actual competition. Tanongsak is another dude I can't get who is he sponsored by. When he was with Bonny, he was using VTZF2LCW and wearing SHB-F1NLTD flash tago yellow/orange. (See SEA GAMES on youtube.) To be honest he's switching around until I can't tell why he has the YY stencil on it sometimes. When he won the Denmark Open, he's apparently under Yang Yang, but the shoes were SHB-65W blue/white/black, and VT80ETN. I guess you can't make proper stuff when you're constantly cloning other brands' paint schemes.