Yes, it's an OEM, but as RPB batteries continue to be on "shorthand" I've finally given up.
I found a reputable retailer, which is an RPB efficianito. He offers a 48v 17.4Ah battery. For less than the "standard" RPB battery. It uses the Hialong Type one case/mount. I may get a second from him.
biggamebikes dot com. The owner/operator is nice, knowledgeable, helpful, has a proactive site. He offers RPB accessories too. He's in the UK, but his batteries are dropshipped from the factory in PRC and have free delivery. WAY COOL!
After that, I've found that case style is easily available. I'm investigating the building of my own cells/BMS/case. Using LG, Sony, Samsung, or Panasonic cells. I'm not into using knockoffs. What do you think, as the RPB battery is still intermittently available? If you use a Bluetooth BMS, you'll be able to have another whole layer of data. I may consider a new BMS for my RPB cells, and put in a Hailong case. Why not?