LS-X is a proven, fast acting, silicone paste which is used as an effective external leak sealer and jointing compound. 
It is designed for use on hot and cold water services, including potable water.
Never sets rock hard so joints can be easily undone.  
Does  not shrink or crack with age.
 
Fernox LS-X External Leak Sealer
50ml
Ready to use - no mixing
Ideal for use on compression joints & screwed fittings
WRAS approved