A slider includes a substrate having a trailing edge, a leading edge opposite the trailing edge, and an air bearing surface connecting the trailing edge with the leading edge; a read/write transducer formed at the trailing edge; and a coat layer attached on the trailing edge and covering on the read/write transducer. The slider further includes a protection layer for shielding the read/write transducer thereby preventing the read/write transducer from damaging during a laser soldering process. The present invention can prevent the read/write transducer from damaging during the laser bonding process and, in turn improve the reading and writing performance of the slider. The invention also discloses an HGA and a disk drive unit.