Famus, it's a wicked good conditioning agent. I don't know specifics but a lot of curlies love it.
Some info:
Lotioncrafter BTMS - Lotioncrafter LLC
Conditioners Containing Behentrimonium Methosulfate | Curly Nikki | Natural Hair Styles and Curly Hair Care

My recipe last night didn't turn out as planned. My original FSG with BTMS didn't have enough BTMS so back to the drawing board. I decided to make it from scratch instead of doing a test sample with 1 3oz tube of FSG. I get the Flax extract done, the herbal extract done, mix them together, get the BTMS in and finally to the right temp.....
Power goes out at 7:40pm
I'm sure it was due to the fire and they wanted to cut power to those affected and went into overkill. At 8:40p I finally went to bed, late. The power comes on at 10:12p and the electric company calls to let me know at 10:45p, uhhh thanks.

So this morning I reheated it and blended it up. We'll see if it's shot when I get home.
Southern Colorado Curly
Mix of 2s med-low porosity, med-fine texture, lots of hair