Yeah I tried stealing one off google.
Theyre 4 stroke pistons for gas motors, but ... theyve moved the skirt support inward right to where your slicing the linear window.
Ummm stolen image?
Having the support there makes the piston strong enough you can make a 4.350 bore bbc piston weigh 740 grams which is sbc stock piston weight, point being theres gotta be alot of load going on in that area of the piston.