The UL listed Chief CMA 115 ceiling plate is designed for ease of installation with any height of drop ceiling
Chief Cma-115 6.0 X 6.0 Inches Ceiling Plate With 1.5-inch Npt Opening - Black available on December 05 2016 from TechForLess for 38.49
UPC bar code 841872002514 ξ2 registered April 03 2016
UPC bar code 841872002514 ξ1 registered September 12 2015
Product category is Mounting Kits Electronic
By using any length of standard NPT 1.5 inch pipe threaded both ends, you can extend the height capabilities to meet your needs.