I came up with an "add-on" effect for Detour De Force by John Bannon - and so I needed 2 force decks to "create" my invention. Of course, Penguin Magic always has what you need. Why shop online anywhere else? It's all right here. You can watch a video of this review on youtube. My account is "MagicOrthodoxy."

These forcing decks are an essential tool for any card magician. While the deck may not be the highest quality that bicycle produces, the effects that can be done are some of the strongest. My favorite is a trick called “Extreme Mental Effort” found on a DVD by Derren Brown called “The Devils Picturebook”. When done correctly this is one of the strongest card tricks I’ve found. The decks only downfall is you are limited to one, possibly two tricks with an audience before you would give the secret away. I have purchased 3 of these decks, each with a different card obviously, to increase the number of effects I can do. This deck is well worth the price given the number of its uses. It is more than a forcing deck as you can make gaff cards, or if you have a trick that involves a duplicate card, you will not have a shortage. Because of these reasons I give it 5 stars!

Great for forces but also really good for making gaffs with (especially T and R effects). You can also make you're own svengali decks using a one way force deck.

I would recommend getting at least one of these decks to put in your magic box because I find they always come in handy.