If cells match from two sheets, copy entire row to new sheet function

Hi everyone, Im 100% confident someone here has an answer for my problem.

So, currently I have a spreadsheet ("retail inventory") with part# listed in column B ( this sheet is physical inventory that I have on hand.) I also have another spreadsheet in another workbook that has a list of 15000+ inventory items, part# in column A, along with descriptions,costs,vendors,etc,etc in following columns. I would like to have a function that says:

If a cell from sheet "retail inventory", Column "B" is equal to a Cell in Sheet "Master Inventory", Column "A", Copy the entire row of data from Sheet "Master Inventory" to another sheet (or to the "retail inv" sheet for all I care). Basicly I need all the descriptions,vendors,pricing,etc from the master list to be transferred to each part number from my on-hand retail inventory sheet. I have some experience with excel but dont know if a macro? or function would be the way to solve this.
Any help would be greatly appreciated.
Thanks-