It is this litter tray system:
https://www.amazon.co.uk/dp/B097PYYFZ1?ref=cm_sw_r_cso_cp_apin_dp_7P5F5J62S...
Cleaned up and works well.
Use with this: https://www.amazon.co.uk/dp/B00CWR7HFK?ref=cm_sw_r_cso_cp_apin_dp_1900SE3KC...
Or buy separate insert and buy litter separately: https://www.amazon.co.uk/dp/B01J5GE3MA?ref=cm_sw_r_cso_cp_apin_dp_JR2X7KAVA...