WHAT DOES 13B ROTARY MOTOR FOR SALE MEAN?

I purchased my MRS 3sgte again in 2020. Parker from NW Motor s known as me and advised me I was obtaining a 1-of-a-variety, clean up 3sgte motor. and he didn’t lie. I’ve got the pictures to confirm it just before set up. I have never viewed a motor this thoroughly clean. Seems like it just arrived from the assembly line.Nothing negative also sa