Name: Sunnah of Wudhu, two units of Wudhu
Ruling: Sunnah, recommended, voluntary
Timing: whenever one performs wudhu. It is permissible to pray these units even in the disallowed times, as if one waits the reason for which these two units are performed will pass.
Method: Two regular units, with no additional special supplications.
Abu Huraira narrated that Allah’s Messenger (peace and blessings be upon him) said to Bilal, “Tell me about the most hopeful act (i.e one which you deem the most rewarding with Allah) you have done since your acceptance of Islam because I heard the sound of the steps of your shoes in front of me in paradise.” Bilal said, “I do not consider any act more hopeful than that whenever I make ablution (wudhu) at any time of night or day, I offer salah (prayer) for as long as was destined for me to offer.” (Bukhari and Muslim)
Uqbah bin Amir al-Juhani reported the Messenger of Allah(ﷺ) as saying, “any one performs ablution and performs the ablution perfectly and then offers two rak’ahs of prayers concentrating on them with his heart and face but paradise will necessarily fall to his lot.” (Abu Dawud, Sahih by Sh Al-Albaani)