This is a 3d Printed Vent that can be used to fit a round hole. They are a two piece product and simply screw together. The size indicated is the HOLE size that the vent is designed to be used with and holes should be CIRCULAR or the vents will not fit propperly.
Note: These vents are all manufactured to order, so depending on your order and if there are any other orders currently being made, there could be a short delay (usually 1-5 business days) between placing your order and us being able to ship it out. Using this method allows us to offer you a much better selection at much lower prices than if we have to build and maintain an inventory of every item.