QUOTE(sw.boutique @ May 31 2013, 11:02 PM)
So does it mean that this stop cock in my bathroom (first posting) is 3/4" since it controls the valve for the water tank?
I suppose I can remove the stop cock knob cover cap (the one with blue dot in the middle) and replace with a nicer looking cover cap?
The water coming to your toilet from the water tank is call outlet. Which mostly is using 1/2" pipe. While from the meter outside to the water tank is 3/4" pipe.
The stop cock in your bathroom is to stop the water coming to the toilet tap. Since the pipe is coming from the tank and to your toilet, it is an outlet pipe. And size 1/2".
You cannot simply replace the knob. Each brand have it own design. Each brand can replace back it own brand parts. Unless those common parts. Ex. rubber washer.
Maybe those expensive type like grohe, kohler etc have an option to change the cover and knob design. But still have to using back it own brand.
So you have to hack it out and replace the whole stop cock.