The Maytronics Dolphin Spring Filter Kit - Pack of 4 (Item 9991468-R4) is specifically designed to to fit the following Pool Cleaners:
Dolphin Nautilus with Clever Clean
Dolphin S50
Dolphin Active 10
Dolphin S300i
Dolphin Prowler 910
Dolphin Echo
Dolphin Saturn
Dolphin Cayman
Dolphin E10
Dolphin Escape
Dolphin Encore