AO31-204: 510Wx1020Dx1420Hmm (Double-sided 4-step staircase)

AO31-205: 540Wx1240Dx1720Hmm (Double-sided 5-step staircase)

AO31-206: 580Wx1410Dx2000Hmm (Double-sided 6-step staircase)

AO31-207: 620Wx1580Dx2290Hmm (Double-sided 7-step staircase)

AO31-208: 660Wx1760Dx2570Hmm (Double-sided 8-step staircase)

AO31-209: 690Wx1940Dx2860Hmm (Double-sided 9-step staircase)