Where can I buy Sealant Tape Used for Applying Sealants? Drainage and wastage systems and plumbing help, advice and answers

[LizMac42]

I saw a great video on You Tube about applying sealants with the use of a special masking tape which looked liked Sellotape.
He taped a line of it above the sealant area - then a line of it below leaving a space for the sealant to be easily applied.
I found some sealant tape at Homebase but it wasn't the single tape - you had to apply both top and bottom at the same time and it was really difficult to get straight. I ended up cutting it down the middle but this was very fiddly.
Does anyone know where you can buy SINGLE rolls of this tape as in the YouTube video?

[tileclipproman]

you dont need tape,anyone can do a good silicone job,go back to youtube
and enter,how to silicone a shower in a static caravan.

[LizMac42]

'Anybody' does not include me - I have tried it before and got into a right mess - but I will watch the video and see if I can improve - I did find it easy using the tape though.