STUMPERS CLXXIV

This is a rebus describing something that would make it hard for you to write a letter:

WR = EE

What is it?

HINTS:
#1: Read the = as "is."
#2: Read the EE as "twoEs"

Answer:

WR is two Es
[wrist woes]

Credit:
The Enigma
March, 2016
EEYBOSH