Besi panjang yang ditekuk membentuk sudut 90 derajat, mirip seperti huruf L.
Siku 3x3 A ukuran (25x25x1.8mm)
Siku Besi 4x4 A ukuran (35x35x2.0mm)
Siku Besi 5x5 A ukuran (45x45x3.0mm)
Siku Besi 3x3 KS ukuran (28x28x2.0mm)
Siku Besi 4x4 KS ukuran (40x40x3.0mm)
Siku Besi 5x5 KS ukuran (48x48x3.5mm)
Siku Besi 6x6 KS ukuran (60x60x5.0mm)
Siku Besi 7x7 KS ukuran (70x70x6.0mm)
Siku Besi 8x8 KS ukuran (75x75x6.5mm)
Siku Besi 9x9 KS ukuran (90x90x8.0mm)
Siku Besi 3x3 SNI ukuran (28x28x2.5mm)
Siku Besi 4x4 SNI ukuran (40x40x3.5mm)
Siku Besi 5x5 SNI ukuran (48x48x4.5mm)
Siku Besi 6x6 SNI ukuran (60x60x5.5mm)
Siku Besi 7x7 SNI ukuran (70x70x6.5mm)
Siku Besi 8x8 SNI ukuran (80x80x7.0mm)
Siku Besi 9x9 SNI ukuran (90x90x9.0mm)
