Dendrobium formosum Roxb. var giganteum Roxburg ex Lindley 1832, in my experience this one really hates being put in a pot

This species has  nice flowers reminiscent of a white Cattleya.  It can produce foot long canes that will bear short inflorescences that with several relatively large white flowers.  In my experience it will only grow well if it is mounted in a plaque, all my potted plants either languished producing poor growth or died.  Plants mounted in tree fern plaques grew larger and thrived for a years but eventually deteriorated as the tree fern plaque decayed and started retaining too much water.  So my advice is to mount these orchids in a plaque and be watchful for poor growth, that will be a warning sign that the mount needs to be replaced.