For indoor we have been using GWS 8x4.3 props for many years. GWS is out of business now so we (my local club) have been using the HK 8x4.5 props for over a year now. We don't get the runtime we did with GWS but the props are really tough. I used to break two or three GWS props a week and now with the HK props I break a prop maybe once every three or four weeks.