diff --git a/lastools.py b/lastools.py
index e3dfcf0..d0f6864 100644
--- a/lastools.py
+++ b/lastools.py
@@ -2,30 +2,30 @@ import os
 import subprocess
 
 
-def call_lastools(tool_name, las_in, las_out=None, args=None, verbose=True):
+def call_lastools(tool_name, input, output=None, args=None, verbose=True):
     """Send commands to the lastools library.
 
     Requires lastools in system path.
 
     Args:
         tool_name:  name of lastools binary
-        las_in:     bytes from stdout, or path to input point cloud
-        las_out:    '-stdout' to pipe output, or path to output point cloud
+        input:     bytes from stdout, or path to main input data
+        output:    '-stdout' to pipe output, or path to main output data
         args:       list of additional arguments, formatted for lastools
         verbose:    show all warnings and messages from lastools (boolean)
 
     Returns:
-        bytes of output las, if las_out='-stdout'
-        None, if las_out='path/to/las/file'
+        bytes of output las, if output='-stdout'
+        None, if output='path/to/las/file'
 
     Examples:
 
     # Convert xyz file to las and pipe stdout to a python bytes object
-    las_data = call_lastools('txt2las', las_in='points.xyz', las_out='-stdout',
+    las_data = call_lastools('txt2las', input='points.xyz', output='-stdout',
                              args=['-parse', 'sxyz'])
 
     # Clip las_data with a shapefile, and save to a new las file
-    call_lastools('lasclip', las_in=las_data, las_out='points.las',
+    call_lastools('lasclip', input=las_data, output='points.las',
                   args=['-poly', 'boundary.shp'])
     """
 
@@ -33,22 +33,22 @@ def call_lastools(tool_name, las_in, las_out=None, args=None, verbose=True):
     cmd = [tool_name]
 
     # Parse input
-    if type(las_in) == bytes:
+    if type(input) == bytes:
         # Pipe input las bytes to stdin
         cmd += ['-stdin']
-        stdin = las_in
+        stdin = input
     else:
         # Load las from file path
-        cmd += ['-i', las_in]
+        cmd += ['-i', input]
         stdin = None
 
     # Parse output
-    if las_out == '-stdout':
+    if output == '-stdout':
         # Pipe output las to stdout
         cmd += ['-stdout']
-    elif las_out:
+    elif output:
         # Save output las to file
-        cmd += ['-o', las_out]
+        cmd += ['-o', output]
 
     # Append additional lastools arguments, if provided
     if args:
@@ -64,7 +64,7 @@ def call_lastools(tool_name, las_in, las_out=None, args=None, verbose=True):
     # Handle errors, if detected
     if process.returncode != 0:
         print("Error: {} failed on {}".format(tool_name,
-                                              os.path.basename(las_in)))
+                                              os.path.basename(input)))
         print(stderr.decode())
 
     elif verbose:
@@ -72,7 +72,7 @@ def call_lastools(tool_name, las_in, las_out=None, args=None, verbose=True):
         print(stderr.decode())
 
     # Output piped stdout if required
-    if las_out == '-stdout':
+    if output == '-stdout':
         return stdout
     else:
         return None