I can guarentte there 1100
I do recieve there PRINTED catalogue meaning even if it aint 1100 they got to get me 1100 for £35 
I am guessing that the 1100 is the model number.
Most PA system speakers are around £150 for around 500W (each).
I doubt you will be able to get 1100W pc speakers for £35, 1100W PC speakers, never heard of anything like it

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That info was copied and pasted from the link you gave which said 28W which is a lot more realistic.
If you want to get some speakers for your PC, hook up an amp to your sound card, preferably a high-end Creative sound card and then put some 100W Yamaha studio monitors around your room if you really want good sound quality. Not £35 28W 2.1 PC speakers.