Pharmacology - Swim woud like to know about some pills.

[port 21]

Swim recently acquired some pills he had never tried before. He said the following to me:

I got these pills from a reliable friend, but ive only ever done pills once before, not including various legals.

These pills are called doves, and, naturally have a dove imprint on the pills.
Ive tried rolex's once, wich were pretty awesome, but i like to know whats going into my body and the effecs.

Does anybody know what would be in them? What dosage for a relatively new user and what kind of come down to expect and how to lessen the comedown.
Im in the Uk (london to be precise) so people know where its coming from, which should help identify them quicker.
My friend told me they had MD and speed in. But i dont fully trust him. Any insights would be awesome.