Product Details
Size: 9.75″ × 7.5″.
Amazon
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Sheet count: 100 sheets.
Amazon
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Ruling: ½‑inch primary ruled lines with space (for drawing/illustration) for younger writers. (Primary format)
Amazon
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Assorted solid colors (for cover variation) – noted in “multiple colors” version.
Amazon
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Brand: Amazon Basics.

⚠️ Notes / Clarifications
I found a listing for a 15‑pack version of this size and ruling under Amazon Basics.
Amazon

The exact “3‑pack” version you asked (3‑pack assorted colours) did not clearly appear in the sources I found, though other pack quantities (like 15 or 4) do.

Make sure to check whether the pack count is actually 3‑pack (as you mentioned) or a different quantity; pack size can affect price.

The ruling description says “extra wide ½‑inch primary ruled lines” – good for young children learning to write.