Drop-down select not required

Can the select be optional

[TheKG]

I have a PHP page to sell pants in several styles and sizes. I already have a drop-down list for the customer to select the size they want. The problem is that not all sizes are pre-hemmed; those that are not can be hemmed at no additional charge. How would I offer a separate drop-down only for those sizes that are not hemmed so the customer can choose to have them hemmed to their liking?

I am using <select> with option value=select to display the available sizes. Is there another option value that can be used to indicate the hemmed length only on those that aren't pre-hemmed?

[not2easy]

Maybe add a suffix to the product name? For example if a pair of pants is called /product12345W-L/ The unhemmed might be /product12345W-C/ so long as the free custom length is explained in the description for those products.

Do the un-hemmed products currently have the same product name as the hemmed version?

[TheKG]

There are three style numbers, each available in 2 colors and are pulled onto the page using a fetch_array. What I was hoping to achieve was an additional drop-down used only if the customer wanted hemming on the unhemmed pants. If I added a suffix to the unhemmed so they would appear as another style I see how I could then offer a separate drop-down to select hemming length. The problem I see with that is that even the ones that are pre-hemmed would have that separate drop-down which I believe would be confusing.