Rat Valve Non Return Sewer Guard Stainless Steel Double Flap 4" 110mm One Way

I haven't installed it yet, but the design is very clever. I first thought there was too much gap for a rodent to get their claws in and lift the flap/s, but if they did, the teeth would dig into them harder, the harder they tried to get through. Flaps seem to move very easily the other way. They can reverse out I expect. I'm thinking two flaps makes it more than twice as secure.

Perfect

A good solid device , the week and half I had it fitted no rats although we weren't getting them every day . Mine blocked up as I had not checked it in a week I couldn't say how long it took to block as when I removed it a great wad came out behind it . I couldn't swear the block had trapped on the flaps . Will refit tomorrow and pay extra attention to the installation

Have been buying this product from a drainage supplier for over a year now, found this product to be the exact same make a model for half the price, would highly recommend

Great product, had this installed recently and have had no issues at all. Great value for money, would highly recommend!!

Absolutely superb piece of kit. Such brilliant value for money. Highly recommend!

Highy recommend!!!I was a bit suspicious when I saw how cheap the rat blockers were. But when they arrived they were exactly the same as the rodent valves I have been paying over £120 for. I am saving myself nearly £50 each time I buy one. I would recommend them to other drain engineers who are looking to save themselves a bit of money. But don't tell my customers how cheap they are!

One improvement you could add is to round the corners at the base. This would improve flow and stop tissues catching on the 90o angles on the flow side.