Most people say the weight of the tenergy rubber is the one of the biggest trade offs for using such consistantly playing table tennis equipment. Although we could start off by saying that table tennis rubber width is always going to change the weight I want to focuss on how the weight and density of the medium hard sponge is the same for tenergy 05, tenergy 64 and tenergy 25. The surface of thickness and compostition is exactly the same for all the Tenergy rubbers also. So the only difference between the Butterfly tenergy series is the pip width and spacing.
The distance between the tenergy 64 pips is the largest and the pips are the thinnest. This makes tenergy 64 the lightest rubber in Tenergy series.
The width of the pips of tenergy 25 are thickest. They actually much thicker than 95% of table tennis rubbers. The space between the pips is the same as tenergy 05. Because of the extra high amount of rubber the Tenergy 25 is the heaviest in the butterfly tenergy series.
The pips of the Tenergy 05 have a medium thickness and are spaced like your average rubber. This makes tenergy 05's weight the lighter than tenergy 25 and heavier than tenergy 64.
They all weigh between 45 grams to 50 grams each once they have been cut to fit on an average size blade. Tenergy 64 is between 45 to 48 grams, tenergy 05 is between 46 to 49 and tenergy 25 weighs between 47 to 50 grams.
Don't forget every blade's head size is different and what one user tells you will be different. I have personally weighed over 20 sheets of tenergy and have found that there is almost only ever a few grams difference. This depends how you cut also.
Just a few rubbers to help you get an idea. The softest high tension rubber Butterfly makes is Solcion. This weighs at 40 grams cut. The fastest rubber Butterfly make is Bryce Speed and that weighs around 46 grams.
You can't compare weight directly but you can use the density function to give you a very accurate idea of the weight of Butterfly rubbers by clicking here on this online store easily
Hope this helps