3 x 50ml Tubes FERNOX LSX External Leak Sealer Jointing Compound WRAS Approved. This listing is for a set of 3 tubes of... Original !! New and sealed. Buy with confidence LSX External Leak Sealer in Yellow Tube 50ml Jointing Compound LS-X Fernox Ideal for use on compression joints and screwed fittings Never sets rock hard, joints can easily be undone Ready to use, no mixing Does not shrink or crack with age Suitable for use from below freezing point to above boiling point of water Completely safe to use with drinking water WRAS – Approved Product 50ml in each