SRT "Self Reaming, & Tapping" screws are the default type screws shipped with LCN closers, when a specific screw type is not specified.
There are 3 standard lengths of SRT screws:
1-3/8"
1...
LCN "does not" recommend the use of SRT screws is wood doors. LCN "only" recommends the use of Wood Screws in wood doors and frames, as noted on the installation instructions.