Boss RC-10R Rhythm Loop Station Pedalcode: RC-10R£258.00
Boss RC-5 Loop Station Effects Pedalcode: RC-5£185.00
MXR Clone Looper Pedalcode: M303£159.00
Boss RC-1 Loop Station Guitar Effects Pedalcode: RC-1£106.00
A looper pedal isn't really an effects pedal in that it doesn't add anything to your signal, but it captures it and plays it back in loops, allowing you to create multiple layers of your playing in real-time. A looper captures sequences of music one piece at a time and allows you to play over the top of layers and turn layers on and off so you can arrange your composition live.
Most looper pedals give you control over the parameters of your sequences, such as the length and speed of your sequence, and the amount of layers you can record is dependant on the pedals storage facility - for example, if a pedal has 10mins of looping available, you could create a 30-second loop with 20 layers. Some more complex looper pedals let you create sequences of several minutes in length - with unlimited overdubs!