This is a wonderful product for grown ups to sort the mixed sensory base mess at the end of play, and for little ones to have a fun addition to their sensory play ! 
A chunky 18mm sifter which sits in the rim of your large trofast tray and almost fills the entirety of the small trofast tray
 It also has handles so can be held over a tuff tray or anywhere to sort small to large sensory base items, or to prospect and forage out and about ! 
It comes with interchangeable 3mm MDF 'plates' that you swap and change to sift different sized items, so if you want to separate your sand and your rice, you use the ones with the smallest holes to separate them.
 The rim of the sifter is 18mm deep, so it will store all plates at the same time and is deep enough that you can pour quite a lot in and it won't spill over the edges (Please note that we can not 100% guarantee that some small pieces of rice won't fall through, but we have made the sand holes just 1.5mm so it fill filter all if not nearly all ! 
Then there is a larger holed plate for separating chick peas from larger items like buttons, coins etc. 
There is also a solid plate, so the sifter can be used as just a sensory tinker tray or mark making tray too 
So this really is a fabulous multi use must have in any sensory play environment !