Tirmidhi

Explanation:
1:
The "Musabbihat" are those surahs which begin with "Subhan Allah," "Sabbaha," or "Yusabbihu."
These are:
Bani Isra'il,
Al-Hadid,
Al-Hashr,
Al-Jumu'ah,
As-Saff,
At-Taghabun,
and Al-A'la.

Note:
(In the chain of narration, Baqiyyah ibn al-Walid is a mudallis narrator,
and the narration is in the form of 'an'anah.
Also, 'Abdullah ibn Abi Bilal al-Khuza'i ash-Shami is "maqbul" (acceptable) only when corroborated,
and he has no corroborator here, so the narration is weak.)

Explanation:
1:
Those surahs in which (Sabbaha, Yusabbihu) or (Subhana Allah) appear at the beginning.

2:
There are numerous narrations from you (sallallahu alayhi wa sallam) regarding the surahs and supplications to be recited at the time of sleeping, some of which the author has also mentioned. It is entirely possible that the Noble Prophet (sallallahu alayhi wa sallam) would recite all those supplications and surahs, or, depending on his energy and alertness, would sometimes recite some and at other times others.

Note:
(In the chain of narration, Baqiyyah ibn al-Walid is a mudallis narrator, and the narration is with ‘an‘anah. Also, ‘Abdullah ibn Abi Bilal al-Khuza‘i al-Shami is considered maqbul (acceptable) only when there is corroboration, and there is no corroborator for him in this case, so the narration is weak. Al-Albani has written “weak chain” (da‘if al-isnad) in the first place in Sahih al-Tirmidhi, and “hasan” in another place, whereas in Da‘if al-Targhib (344) he has called it weak.)

Benefits and Issues:
Benefit:
By (al-Musabbihat) is meant those Surahs of the Noble Qur’an in whose beginning the word (Subhana, Sabbaha) or «یُسَبِّحُ» has come.
And these are seven Surahs:
Bani Isra’il... al-Hadid... al-Hashr... as-Saff... al-Jumu‘ah... at-Taghabun... al-A‘la.