(By Tawny Banh) Butterfly Tenergy 19 is the newest performance rubber from the Tenergy series, encompassing the “spring technology” and “high friction.” It comes in 3 sponge thicknesses: 1.7 mm, 1.9 mm, and 2.1 mm. The thicker sponge is the most popular amongst the offensive players. The sponge hardness is 36 degrees which is soft […]