If the variant you want is sold out, you can pre-order here.
Size 5XL is available in black and heather grey only. The heather grey is 50% cotton, 50% polyester (Gildan).
Sizing (chest width, length) in inches:
(Actual size may be +/- one inch)
XS – 16.5, 27
S – 18, 28
M – 20, 29
L – 22, 30
XL – 24, 31
2XL – 26, 32
3XL – 28, 33
4XL – 30, 34
5XL – 32, 35