Excellent, highly visible core block made from tough, impact resistant plastic, these blocks have been made form a mould which give them indented markings in the form of symbols and numbers which users can simply use a permanent marker pen to fill in to their requirements, e.g. loss, gain etc. They come flat, with scores and snap together easily, this reduces the space they take up and in turn reduces on shipping costs if large quantities are required. These blocks are suitable for H and P size cores and detail the following information: core recovered, depth and loss and gain. A must have accessory on drilling sites, with an easily visible colour.