Collar tabs for the SS-Totenkopfverbände uniform (literally from German: units of the "Death Head", these units were involved in the protection of concentration camps). The skull and number 1 (for the 1st Standarte or regiment) are on the left tab, the right is plain black (by adding pips you can make "lieutenant" ranks: SS-Sturmführer, SS-Obersturmführer, SS-Sturmhauptführer). Bullion by silver metal thread. Edge piping is made of a twisted silver-black cord.
How to sew collar tabs on? Put a collar tab on the collar of the service jacket so that it is not less than 5 mm from the edge. Fix it with a bright thread (which then remove) or glue. When collar tabs sit properly, they need to be sewn with a black thread by the edge.
The black SS service suit was formed in 1932. Since that time, the SS uniform has become a symbol of the Nazi Party. Prior to this, brown shirts did not allow the SS to stand out, as they were too similar to the clothes used by the SA. To distinguish the SS from the SA, Himmler began the transition to black uniforms in the 1930s, and this was a milestone in the uniform of Germany. News feeds, photographs and drawings from that period were full of shots of strong men in black uniforms surrounding Hitler, causing awe and a sense of mystery.
Until October 1934, enlisted personnel from SS-Obertruppführer (Obertruppführer, equivalent to a sergeant) wore a black-and-white twisted cord around the edge of the collar and collar tabs, and junior commanders (lieutenant level) to the rank of SS-Sturmhauptführer they wore a black and silver cord. Higher ranks from SS-Sturmbannführer and above — a 2-mm silver cord. In October 1934, the collar edging was revised, all officers now wore silver edging of collar tabs and collar.
Historical information is provided from Michael D. Beaver's book "Uniforms of the Waffen-SS", volume 1.