A very high quality Huggett Standard noise moderator designed for all air rifles with a 1/2UNF thread (the standard air rifle thread used by most manufacturers such as Air Arms, BSA, Daystate, Evanix, Weihrauch, etc.) The moderator is screwed on like a barrel end. The moderator is designed for calibers 4.5mm and 5.5mm. The length of the moderator is 120mm. Made in England.