Note: There was only a small number of issues with the 'Hammer's House of Horror' title due to Warren quickly copyrighting the 'House of Horror' title in the US but they licensed the name from them for two months, rather than having to overprint a title change on the already printed issues. This would lead to later issues having another title change to 'Hammer's Halls of Horror'. An US #[1] teaser reprint issue was released before #19. #19 had both an UK cover price and an US price variant cover. #20 has two versions with the same contents. One is an UK version with 'Hammer's House of Horror' title/indicia/price and another which is the US version with 'Hammer's Halls of Horror' title/indicia/price. You will be able to find both issues under their respective series titles.