“u” like [oo]
This vowel is used only on the letter “ו” (vav). It sounds like “u” in English. [oo]
When we use the Shuruk, the letter “ו” operates as a vowel letter (like in Arabic [w – و ].
“The Shuruk is the letter Vav with a dot in the middle and to the left of it. The dot is identical to the grammatically different signs Dagesh and Mappiq, but in a fully vocalized text it is practically impossible to confuse them: Shuruk itself is a vowel sign, so if the letter before the Waw doesn’t have its own vowel sign, then the Waw with the dot is a Shuruk and otherwise it is a Waw with a Dagesh or a Mappiq. Furthermore, the Mappiq only appears at the end of the word and only in the letter He (ה) in modern Hebrew and in the Bible it sometimes appears in Aleph (א) and only in some Bible manuscripts it appears in the letter Waw, for example in the word גֵּוּ (‘torso’) [ɡev]. Compare for example Waw with Dagesh in מְגֻוָּן [məɡuvˈvan] ‘varied’ (without niqqud: מגוון) as opposed to Shuruk in מִגּוּן [miɡˈɡun] ‘protection’ (without niqqud: מיגון); see also orthographic variants of Waw.” wikipedia
Kubutz אֻ Or Qibbuts
It sounds like the letter “u” in boo.