Similar to a commercial pull bar. The end that gets thwacked is purposefully overly thick, as this was a failure point in previous versions (these are usually made of steel). 

I printed with 3 wall loops and PETG. 

Print on it's side and you won't need supports. Brim is recommended. 

V2 model added, which removes some thickness from the tall end in favour of a more gradual ramp transition to add further strength.