Table Array Search

Hi,
I'm still working on my costing sheet and I'm trying to enter a formula to allow for a searchable drop down.

My intention is to be able to search on the drop down on the Cost Sheet.

I enter the formula =ISNUMBER(SEARCH($I$1,Table13[Details])) to give me a search criteria for column B on the pricing table.

When I try and filter just the true cells using the formula =filter(Table13[Details],ISNUMBER(SEARCH($I$1,Table13[Details])),"Not Found"), I get an error an error message "This function isn't valid and it highlights "filter" in the formula field.

I've seen it work on a tutorial on You Tube.

I've uploaded the workbook as it stands presently.

Any help would be appreciated.