US Issue chevrons available for infantry, cavalry/engineers, and artillery. Available in the following ranks:
 
Corporal
Sergeant
First Sergeant
Quartmaster Sergeant
Sergeant Major
 
All are made using 1/2" wool tape, but can also be made in silk or velvet tape for $5 per set. 
 
If ordered with a coat or jacket, chevrons can be attached at no additional fee, just make sure to specify you want them attached at checkout.