The Instrument Is Designed Mainly For Indoor Use, The Laser Beam Is Visible At 5M In Daylight And 100M In Darkness At Night.Parts:Switch For Horizontal Lineswitch For Vertical Linebattery Cover Led Indicationlaser Window Horizontal Laser Linevertical Laser Line Base Lockoperation:Technical Data:Horizontal Accuracy: 0.5Mm/Mvertical Accuracy: 0.5Mm/Mwavelength Of Laser: 650Nmpower Of Laser: 1Mwself Leveling Scope: 3Self Leveling Time: < 8 Secretarypower Supply: 2 Lr6 (Aa) Batteriesoperative Distance: 5M