if the silver ones are the same as these, mine do 3-4-4-11 415mhz 2.2v
i can go lower in timings but haven't really messed with it, they do 500+ with 5-5-5-15 too.
right now im typing this with 3-3-3-9-18-t2 2.2v, bin running for several hrs.
going to do othos when i go to bed