When cutting new threads on soft stock a little alignment is helpful - those die guides can be inserted in the die holder below the die and then act as a guide for getting the threads started.

The guides are modeled after common DIN 225 guides (affiliate link) - usually those guides are not heavy duty and are made of cast aluminium since they only used to align the die - they work fine when printed out of PLA or PETG and if they break, just print another one.

They work great with an off the shelf die set (affiliate link) from various brands like RUKO, EXACT and such).

Printing

• concentric top and bottom
• 100 % infill or maximum walls
• no supports required
• no assembly required