Review (1/5): Not impressed is putting it lightly.
If I could've left 0 stars I would've but you aren't given that option.. I'm no stranger to threads or COG's but these were the worst I've ever used. They remind me very much of a different style of COG's & given my issues remind me of a similar set of problems a well known vendor had w/their mini COG's, only that well known vendor acknowledged the problems & made things right w/everyone who bought the bad one's. You will absolutely NOT find that level of customer service here.. Not 1 of these engaged or stayed engaged which was VERY frustrating not just because I wasted money but because I bruised my face & caused swelling for nothing. Had even 2 of these worked I would've been happy & chalked it up to something but not even 1 worked. I actually msg'd seller after using 4 of the 12 but got a reply that was of NO help. I assume a language barrier was the reason, or part of it anyways.. I've definitely learned my lesson.. Buy threads from a vetted vendor, not on Amazon where you have no idea how they are stored, how old they are & a plethora of other important criteria, or if they are indeed what they were advertised as. Plus there is zero support should you have questions. I've used all kinds of COG's incl 4D, 6D, heavy duty, lighter duty, etc., so was curious about 8D's & I had a gift card I wanted to use up so I thought why not.. Big mistake! These did not feel anything like even the 6D's or 4D's I've used in the past but felt like simple bi-directionals. The areas I put these in should've been easy for a good thread to hold. I did not try using these like heavy duty COG's because they are smaller gauged, 23g & only 60mm long so they should've engaged & they should've stayed w/even minimal lift but they either did not engage or they quickly came un-engaged. I will never buy threads off Amazon again & feel like a bonehead for even trying.. Save yourself your money, bruising, swelling for nothing & being totally frustrated. Buy from a well known vendor who sells tons of these, has customer support, stores them correctly, where they have basic quality control & where if you have a major problem w/them due to them being faulty, you won't have to go through the huge headache of trying to get the seller to do the right thing.. That is a whole separate issue.. You have been warned..