Apple is still deciding how to build the hinge for its rumored foldable iPhone Ultra. Insider Fixed Focus Digital says the company is choosing between two methods to create a nearly invisible crease.

One option uses liquid metal, an amorphous alloy known as metallic glass, which offers flexibility, scratch resistance, and shape memory. The other is 3D printing, which is cheaper and easier to produce.

Apple’s choice depends on chip supply. Limited memory availability favors the liquid metal hinge for small batches. If memory supply improves, Apple may switch to 3D printing. The final decision is expected by the end of July.