LetsGrow123 is the owner of the gripping trainer website. He also posted here as ykm123321 in an effort to promote that site and the related video site. Please take any product endorsements as very likely to be biased.
Started ~ 2002 14.5 cm BPEL and 13 cm MSEG.
2008: Got serious, Measured ~ 15 cm BPEL and 14 cm in MSEG
1/12/2014: Measured BPEL 17.5 to 18 cm, MSEG 15, BEG 16.5
Keep an open mind and a closed wallet... unless it's open to making a donation!