This is a 16x7 Composite Pattern Propeller from APC. FEATURES: Composite Construction. INCLUDES: One Gray 16x7 Propeller. REQUIRES: ALL props require balancing, this is VERY important, use TOPQ5700. May need prop reamer, use GPMQ5005 (SAE) or FOXQ1520 (Metric) SPECS: Center Hole Diameter: 5/16" approx. Propeller Diameter: 16" Propeller Pitch: 6 COMMENTS: Four stroke engines are typically higher torque engines and should use the larger props indicated in the range. Recommended prop ranges will vary depending on your particular engine and airplane. The Chart below represents average prop usage and should be used as Only a General Guideline. Always refer to the manufacturer"s instructions included with your engine. Engine Size 2-Stroke 4-Stroke .049-.051 5.5x4, 5.5x4.5, 6x3, 6x3.5, 6x4 N/A .09 -.10 7x4, 7x5, 7x6 N/A .15 7x6, 8x4, 8x5, 8x6, 8x7 N/A .20 -.25 8x6, 8x7, 9x4, 9x5 9x4,9x5,9x6,9x7 .29 -.35 9x6, 9x7, 9x8, 9.5x6, 10x4, 10x5, 10x6 N/A .40 9.5x6, 10x4, 10x5, 10x6, 10x8, 10x9 11x6,12x6 .45 -.50 10x8, 10x9, 11x4, 11x5, 11x6, 11x7, 11x7.5 N/A .60 11x5, 11x6, 11x7, 11x7.5, 11x8, 11x9 11x8,11x9,12x6,13x6 .71 -.80 12x6, 12x8, 13x6, 13x8, 13x10, 14x8 N/A .90 13x6, 13x8, 13x10, 14x6, 14x8 11x9,12x8,14x6 1.08 14x8, 14x10, 15x8, 16x6 N/A 1.20 14x8, 15x8, 16x6 14x8,15x8,15x10,16x8 1.5 16x8, 16x10, 18x6, 18x8 N/A 1.8 18x8, 18x10, 20x6, 20x8 N/A 2.1 20x8, 20x10 N/A 2.7 -3.0 22x8, 22x10, 22x12, 24x8, 24x10, 24x12 N/A tjt 030502 ir/kh