Mapei flexicolor ready mixed grout

Good preparation for grouting is key you need to pay close attention to silicone joints and carefully remove old grout.Ensure it is all removed prior to applying your grout using a flexble grouting tool and apply a square metre at a time.I like to have a few clean tiling sponges to hand and have 1 damp and 1 dry and rinse and dry.As the grout dries you may find it gets drawn into the joint so its common to have to do it twice and 3 times with mosaics to achieve a good smooth uniform finish.

Depends if it is waterproof or not,you dont need flexi on walls only timber floors.

I wouldn't, always use powder grout which you mix up yourself in wet areas. Much better water resistance and will last much much longer

Yes have used this many times on tiling jobs in showers and 6 years later it still looks good

Yes you can use the ready mix grout in a shower.

Yes you can use it for showers.