It fits into the group handle instead of the regular filter. Backflushing your coffee machine helps to remove coffee residue that builds up inside the group head. The blind filter can be used in conjunction with cleaning tablets. Make sure your coffee machine has a suitable pressure relief valve and that the diameter is correct for your coffee machine. HOW TO USE IT? Remove the filter basket from the portafilter and insert a backflush disc. Spoon approximately 0.5 teaspoons of backflush cleaner into the basket. Place the portafilter back into the brew group and turn on the pump. In approximately 20 seconds the pump will become very quiet. This is a result of the pressure now building up. Once the pressure has built up (quiet), turn off the pump. You will then hear a sound as the cleaner is blown into the brew group, through the three-way valve and emptied into the drip tray. Repeat this process until the foam coming out of the drip tray is clean. Remove the handle and rinse the detergent out of the handle. Reinsert the handle into the machine and do a few more backflushes without detergent, using only water. Finally, remove the handle and turn the pump on and off a few times to rinse out the remaining detergent from the brew group. Color: Silver Material: Stainless Steel Size: Length: 70mm. Bottom Diameter: 58mm Diameter: 60mm. Height: 20mm. Package Contents: 1 * Blind Cup, Non-Porous Filter Container Note: Please make sure your coffee machine has a suitable pressure relief valve and the diameter is correct for your coffee machine. The above package contents only, other products are not included. Note: Light and different displays may cause the color of the item in the picture slightly different from the real thing. The measurement allowed error is +/- 1-3cm.