Ph7-70 Acid Neutral Double Sided ATG Tape 19mm x 30m. Permanent adhesive, Ph neutral double sided tape 19mm x 30m. Conservation Ph neutral double sided tape ATG tape gun compatible although a tape gun is not required to use it. 19mm wide by 30m length. Ph neutral tapes are acid neutral, they use a water based acid neutral acrylic adhesive system which will not react with board or papers and can hence be used for conservation purposes.