The 304 and 316 high-strength version quick links are made with a slightly larger nut adding better holding power.

The 304 SS and 316 SS 7mm and 8mm quick links have stamped ratings from the manufacturer. 

Climbing Taiwan's break test videos & results:

8 mm 316 SS Zoutianya:  55.86 kN (test terminated), 69.14 kN, 48.79 kN Video 

8 mm 316 SS Climbing Taiwan: Rated Breaking Strength 30 kN

8 mm 304 SS (high-strength) Ningjing : 68.66 kN Video

7 mm 304 SS Barhar : 52.80 kN, 52.95 kN Video Video

7 mm 304 SS (high-strength) Ningjing : 51.27 kN, 46.50 kN, 50.61 kN Video

CTW 6mm 316 stainless steel high-strength long quick link, 22 kN 

The 304 SS & 316 SS of both 7mm & 8mm long quick links have stamped ratings from the manufacturer.