I managed to find one of the rare "Chess Champion" clocks produced by Looping in the Swiss Kanton Solothurn, which are similar to the famous Heuer clock. In fact, Heuer never produced chess clocks of its own, but only marketed the Looping clock under its own Heuer brand. When and in which quantity the clock was also marketed under the original company name Looping , is unclear. At some time either the owner(s) decided to stop providing Heuer with the clock, or they always sold the clock under their own brand, parallel to the major client Heuer. Looping went bankrupt in 1980 and the brand, patents, machinery and know-how were bought by today's owner of Looping & Amyral. According to Sutter, the chess clock production stopped many years before the bankruptcy in 1980.