Caps and collars to cover a threaded muzzle when the moderator is off. Parker-Hale and BushWear screw-cut collars, and Jackson Rifles protector caps.
Measure, do not assume. Thread protectors are the item people order wrong most often. You need the diameter and the pitch, and imperial and metric threads of similar diameter will start and then cross-thread if you force them. The common British stalking rifle threads are 1/2" x 20 UNF and 1/2" x 28 UNEF - a 20 tpi and a 28 tpi cap look identical in the hand and are not interchangeable. Metric muzzles are usually 15x1 or 18x1. If the rifle was threaded by a gunsmith rather than the factory, ring them and ask rather than guessing.
Why fit one at all. The crown is the last thing the bullet touches and the first thing to get knocked. A bare thread picks up burrs off the slip, and a damaged crown or a burred thread will cost you accuracy and can stop a moderator seating square, which is worse. Fit the protector every time the moderator comes off.
Related: Sound Moderators · Cleaning Kits
