Penta 97 16M are very powerful when properly customized. Sweet spot seems to be smaller than on 18M but when you hit the center the ball may explode. However it is not the advertised 305 g, because with 10 g lead at 9 and 3 and overgrip it is only 308 g unstrung. Probably some quasi-pro stock frame as it came brand new from a former national champion. It was powerful even when strung proportionally with Lux APS @ 25.5/25 kg ref. tension.