Really strong drain clearer wanted

[Thankyou4calling]

Can i buy something off the shelf stronger than the usual Mr muscle type stuff?

Thanks

[Thankyou4calling]

Thanks for the replies. Can i go in a shop, say a plumbers merchant and buy a bottle of Sulphuric acid or caustic soda cystals ?

I don't really want the one shot stuff as that is pretty feeble.

Thanks

[Thankyou4calling]

Thanks for all the info.

It's a sink in the bathroom that's slow to runaway so it can't be a paper product.

I will buy the Oneshot and give it a try.

Thanks all.

[Thankyou4calling]

Thanks for the advice.

I used caustic soda crystals and they worked a treat.

All now running well.