Well lets start off with what it is and how it works. Well it's a plastic casing with a gyroscope ball which can spin in all different ways. To get the gyro started you can either use the string (2 supplied) or your finger, you then hold it in your hand and you move you wrist in a circular motion, this causes the gyro to move faster and faster, you you go in smaller circular motions to make it go even faster. When you get up to around 8000RPM you really have to start trying hard and the faster it goes the hard it is to keep it going.

I got this around 1 month ago for £10 off a site called yoursecretcode (http://www.yoursecretcode.co.uk/?ref=PP9) by completing one of the offers, so i got this cheap to start off with. I saw it on firebox for £24.99 which surprised me, so i though £10 even if it is rubbish i haven't wasted that much.

I got it a couple of days later, and got it out the box. I hadn't a clue how to use it, so i spent half the day playing with it, and then i suddenly got it, it starts feeling 'heavy' and this is when you can tell its working your arm muscles, but as soon as you figure out how to do it, you just want to do it again and again... It gets addictive! Once you figure out how to do it you will always be able to do it.

You then want to try and beat your score (which is the RPM) which is displayed on the screen on the front, it's like a game you can play with yourself. Or as i did i took it to a party and all my friends were wanting to play with it, infact i hardly played with it that night.

The top RPM according to the powerball website at the moment is 15,840 rpm, i am currently at 10,348 rpm, and i'm finding it difficult to beat what i got let alone what the record is.

Regarding your muscles, i certainly feel like my arm muscles are strong than they were. I play in goal for a local football team and i've noticed that if you need to 'palm' the ball away that it is easier now, so i certainly believe this has built up my muscles. i use it for around 5 mins a day sometimes more.

It also seems that the powerballs come with a lifetime guarantee! (http://www.powerballs.com/powerball_guarantee.php ) and it anything goes wrong you can send it back and they will send you a new one. I'm not 100% sure if you have to buy from powerball but i believe that even if you brought it from another shop you can get the lifetime guarantee, but you can contact them shoudl anything go wrong.

One thing you have to be careful with is that don't touch the gyro when it is going around as it can burn your skin, and friend did it a week ago and he still has a mark from it. So be careful.

Overall it is a great gadget and i would recommend it to anyone!