Abstract: A slidable apparatus with adjustable length for aligning and marking spaced apart points for fastening means, such as nails and hooks, for hanging objects is disclosed. The apparatus comprises at least two elongate members and at least one bubble level. The elongate members are slidable relative thereto, each having a first end and a second end. The first ends each have a stopper to stop sliding the elongate members when the apparatus is at its maximum length. The second ends each have a marking member. The at least one bubble level either has a fixed position or adjustable positions to allow rotating of the at least one bubble level.