> ## Documentation Index > Fetch the complete documentation index at: https://docs.sprello.ai/llms.txt > Use this file to discover all available pages before exploring further. # Combining inputs with the Combinator > Pair two sets of inputs: every combination, or one to one. The Combinator takes **two sets of items** and pairs them, so a generator can run across the combinations. It's how you produce a grid—every product in every material, every model in every pose—in one workflow. Add it from the **Utilities** menu. It has two inputs (A and B) and two outputs (A and B); you connect your two sources in, choose a strategy, and connect its outputs to a generator. A Combinator node with two inputs feeding a Generate Image node ## Cartesian: every combination **Cartesian** pairs every item in A with every item in B. Three products and four materials make twelve pairs—and twelve generations. A Combinator set to Cartesian producing every product-and-material combination ## Paired: one to one **Paired** matches items by position: A1 with B1, A2 with B2, and so on. Use it when your two sets line up—five products with their five named colorways. A Combinator set to Paired matching two sets one to one Paired needs **equal counts**. If A has five items and B has three, Sprello shows an error and asks you to even them up or switch to Cartesian. ## When you don't need a Combinator If you want every item in one set to use the *same* fixed references, you don't need a Combinator. Set the varying source to **Each** and the fixed one to **All**, and connect both straight to the generator. See [mixing modes](/concepts/variations#mix-the-modes). Reach for the Combinator when **both** sides vary. ## Good to know * The 500-items-per-node cap applies to the combined total. Twenty by thirty is six hundred—over the limit—so Sprello blocks it and asks you to reduce a side. * The two sources must share a clear relationship. Two unrelated iterating branches can't be combined, because there's no consistent way to line their items up; Sprello flags this when it happens. ## Next Run your workflow and review everything it produced.