Your search for "effervescent tablet" revealed the following:

Sale price £29.47 Regular price £40.00 Sale
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Sale price £35.84 Regular price £50.00 Sale
Sale price £23.29 Regular price £30.00 Sale
Sale price £33.99 Regular price £40.00 Sale
Sale price £29.97 Regular price £40.00 Sale
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Sale price £32.99 Regular price £40.00 Sale
Sale price £23.19 Regular price £30.00 Sale