Your search for "effervescent tablet" revealed the following:

Sale price £36.99 Regular price £50.00 Sale
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Sale price £32.45 Regular price £40.00 Sale
Sale price £41.65 Regular price £60.00 Sale
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Sale price £49.99 Regular price £70.00 Sale
Sale price £69.95 Regular price £90.00 Sale
Sale price £128.72 Regular price £200.00 Sale
On Sale from £34.72 Regular price £40.00 Sale
On Sale from £50.83 Regular price £70.00 Sale