A MEDICFX repair kit or repair gun.
Sticky Tape 4cm wide
Sewing pins with head
Clean the appliance with hot water and wipe the tear/cut down with alcohol.
Spread the appliance out on a flat surface. For a sleeve wrap it around a plastic bottle.
Place the sticky tape under the tear/ cut with the sticky side up.
Mix the silicone as instructed 100/100 or use the repair gun.
Spread the silicone inside the tear/ cut.
Push the sides together and use pins to keep it closed.
Leave for 1 hour or sped up time with a hot hairdryer.
Repeat if there still are holes or dents in the line.
A piece of hard foam is handy to pin the appliance for repair. Push the pins through the appliance in the foam to secure the cut. No need for the tape this way.
For a more sturdy repair where the appliance needs to be stretched you can add a strip of mesh in the silicone at the back of the appliance