Yeah, 3 sizes, 5[sup]1[/sup]/[sub]4[/sub]", 3[sup]1[/sup]/[sub]2[/sub]" and 2[sup]1[/sup]/[sub]2[/sub]"
First ones usually for ODDs and special attachments, second one is for HDDs (and sometimes floppy drives), third one is used for SSDs and laptop HDDs