Spring and Base Pad.
I purchased a plus 3 base plate and spring for the Sig XMacro. I personally think they're both high quality and I've had 0 issues with either after about 950 rounds. The 20th round in the mag may be a little tight until the spring loosens up, but it will hold 20 rounds. My only complaint, which has nothing to do with the items themselves, but the amount of time they take to actually ship what you purchase. I ordered another setup like 3 days ago and it still hasn't shipped. Side note, I'm a little impatient, lol.... Overall, awesome product and company.
