Two bosses of a firm that conned people into buying fake thermal roof paint in an "£8m racket" have been jailed.
Therma Seal workers used "aggressive and fraudulent" techniques to sell a product that did not do what it was meant to, Trading Standards said.
Directors Alan Wilson, 54, of Fazeley Road in Tamworth, and Christopher Wilkes, 45, of Tamworth Lane in Solihull, were found guilty of fraud.
They were each jailed for five years.
A third defendant found guilty of fraud, saleswoman Julie Barrett, 50, of Hewell Avenue, Bromsgrove, is due to be sentenced on 1 April.
The company falsely claimed the coating could reduce heat loss by up to 25% and increase the value of a home, said Dudley Trading Standards, which led the case.
It said in one case a 91-year-old woman paid £13,000 for the roof coating. In another example, Stephen Bannister, from Stourbridge, paid more than £3,000 for the work.
Speaking after the case at Wolverhampton Crown Court, Councillor Rachel Harris, cabinet member responsible for trading standards at Dudley Council, said: "This was a large scale fraud netting over £8m in three years involving a significant number elderly and vulnerable customers.
"To mis-sell a product with so many false claims is despicable, and it left many victims out of pocket by tens of thousands of pounds."