I'm sorry I think I misunderstood your question. This clip was not taken from a set lesson as such. It was one of several translated open sessions that Shaykh Ubayd did this summer during one of the dawrahs. It may be titled 'Q&A session' or something similar.
Wa iyaaki ka thaalik. The date of session is shown on the attachment. I don't know if the audio is available on tape or otherwise but you could try doing a search on the Salafi Duroos web-site and select Shaykh Ubayd where the name of the speaker is requested.