Sierra International 18-3109 Marine Water Tube Guide Sierra Head Gasket Meets or exceeds the original equipment quality Sierra part number: 18-3864 Interchangeable with the following: GLM 35870, Mallory 9-63854, Mercury 27-822844-1, 27-822844T05, 27-822844T04, 27-822844004, 27-822844, 27+184721, 27-8228443, 27-8228442 Fit specific, check part numbers to ensure proper fit