Spanish to English Other Construction / Civil Engineering Blind-rivet nuts

Hi,

I'm translating some product descriptions for an online retail site from Spanish for Spain to British English and am having trouble with a phrase. The product in question is a pack of blind-rivet nuts, but I'm not sure what it is unfortunately. Here is the full description for context:

'Bralo S301206009 - Tuerca acero remachable M6 c/baja minicaja 10p'

It can be found at the following link:

https://www.amazon.es/dp/B008BSH6I2

Having done a little research, I'm not 100% sure about what this is meant to be referring to (or whether the Spanish is particularly great in the first place!). I have a feeling that it is meant to mean 'Counter-Sunk Head', but I am by no means certain. Can someone help please?

Many thanks!