(1) Set of Good Used 150 grit, 2 1/2" stone for general 2-stroke and blind hole cylinders.  I had these stoners custom made4 for when I was boring and honing blind hole Mercury outboard blocks.  They are GY25 style.  Range 2.5 to 3.3.  For use with AN or HN style hones.  I used them in 44ci blocks but can alswo be used for 22-66ci blocks.