Polyester filaments and tows

A polyester filament having a scalloped-oval peripheral cross-section that is of aspect ratio (A:B) about 3:1 to 1.1:1, B being maximum width and A being measured along major axis of the scalloped-oval peripheral cross-section, and having 6 grooves extending along the filament, 3 of said 6 grooves being located on each side of the major axis, 4 of said 6 grooves being located towards the ends of the major axis and being referred to herein as outer grooves, wherein a pair of said outer grooves that are located at the same end of the major axis define between them a lobe at that same end of the major axis and are separated from each other by a minimum distance between said pair of d.sub.1, the width of the cross-section as measured at the lobe being b.sub.1, and remaining 2 of said 6 grooves that are not outer grooves being located between outer grooves on a side of the major axis and being referred to herein as inner grooves, wherein said inner grooves are separated from each other by a minimum distance between them of d.sub.2, wherein bulges in the generally oval peripheral cross-section are defined by being between one of said inner grooves and one of said outer grooves, the width of the cross-section as measured at such bulge being b.sub.2, and wherein the numerical relationships between the widths b.sub.1 and b.sub.2 and the distances d.sub.1 and d.sub.2 are as follows:

• d.sub.1 /b.sub.1 is about 0.5 to about 1;
• d.sub.2 /b.sub.2 is about 0.5 to about 0.9;
• and b.sub.1 /b.sub.2 is about 0.25 to about 0.9.