those are aliexpress specials
Can’t find the link right now but if you search something like, “double skateboard rear light/tail light” it should come up. Comes with a bracket to mount and everything.
They are motion sensing so they’re pretty dope for night rides or if you just want ppl to know when you are braking.
from my build thread for her -
edit - found the link homies:
https://www.aliexpress.com/snapshot/0.html?orderId=8018015434602261&productId=4001198292870&edm_click_module=order_detail&tracelog=rowan&rowan_id1=postArriveV2_1_en_US_2020-08-25&rowan_msg_id=2261801801543459$ce4ba32608894f75a486ac096900b153&ck=in_edm_other
They raised the priced on us - think I got it for $30