Join our monthly mailing list for exclusive promotions! Plumbers, gasfitters and drainlayers. Didn't unblock sink at all,if anything is was more blocked after applications, even when left for hours! The largest choice of diy products. Unblocked the bathroom sink instantly sounded like it was going to explode so knew it was doing it's job! Old (possibly 's/'s) electric boiler, " high, "x" has been painted over but original.