Cat deterrents

[benjersthefish]

After spending around 50quid on various sprays and potions to keep cats out of my garden, I'm thinking of buying this:

http://www.amazon.co.uk/The-Big-Cheese-Cat-Repeller/dp/B000NR8Q1U/ref=sr_1_1?ie=UTF8&s=garden&qid=1209919458&sr=8-1

I was just wondering if anyone here had ever used one, and would recommend it? and also, does it harm birds or other small mammals?

thanks guys