It fits into the group handle in place of the standard filter. Back flushing your coffee machine helps to remove coffee residue which builds up inside of the group head. The blind filter can be used in conjunction with cleaning tablets. Please that your coffee machine features an appropriate pressure release valve and that the diameter is correct for your coffee machine. HOW TO USE IT? Remove your filter basket from the portafilter and put in a backflush disc basket. Spoon approximately 0.5 teaspoons of backflush cleaner into the basket. Put the portafilter back into the brew group and turn on the pump. In about 20 seconds the pump get very quiet. This is a result of the pressure now being built up. When the pressure has built up (quiet), turn off the pump. You then hear a “whoosh” sound as the cleaner gets blown up into the brew group, through the three-way valve and empties into the drip tray. Repeat this process until the foam out into the drip tray is clean. Remove the handle and rinse the cleaner out of the handle. Put the handle back into the machine again and do a couple more backflushes without cleaner…using . Lastly, remove the handle and turn the pump on and off a few times to rinse the remaining cleaner out of the brew group. colour:Silver Material:stainless steel size:Length:70mm. Bottom diameter:58mm Diameter: 60mm. Height: 20mm. Package Contents: 1*Blind cup, non-porous filter bowl Note: Please that your coffee machine features an appropriate pressure release valve and that the diameter is correct for your coffee machine. Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.