This is the original Mk1 coarse thread, 1/2" bsp,  Mk2's use a fine thread which I have in my other auctions.

Please be aware that some late production original Mk1's and the remake based on a Mk2 block use the fine thread, any doubts check or send a photo.

See my other items and I will combine postage, if you would like to buy multiples contact me for shipping discount.