diff --git a/annexremote/__init__.py b/annexremote/__init__.py
index a28f7f5..d85cfac 100644
--- a/annexremote/__init__.py
+++ b/annexremote/__init__.py
@@ -3,3 +3,4 @@
 del get_versions
 
 from .annexremote import *
+from .key import Key
diff --git a/annexremote/key.py b/annexremote/key.py
new file mode 100644
index 0000000..844ab64
--- /dev/null
+++ b/annexremote/key.py
@@ -0,0 +1,193 @@
+# Key - Helper class to hold additional information about keys
+#
+# Copyright (C) 2021  Karl Semich
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of version 3 of the GNU
+# General Public License as published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be uselful, but WITHOUT ANY WARRANTY; without even the implied
+# warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+import collections
+
+class Key(object):
+    """
+    Helper class to hold additional information about keys.
+
+    '''
+    Attributes
+    ----------
+    remote : SpecialRemote
+        The SpecialRemote object this key is affiliated with.
+
+    state : str
+        The state associated with the key, stored in the git-annex branch, if any.
+        May be mutated to update git-annex.
+
+    size : Union(int, None)
+        The size of the chunk of data represented by the key, if available.
+
+    bytesize : Union(int, None)
+        The size of the entire file the key refers to, if available.
+
+    mtime : Union(int, None)
+        The mtime of the key, if available.
+
+    keyname : str
+        The name portion of the key, containing its hash and possible extension.
+
+    backend : str
+        The key backend.
+
+    key : str
+        The whole key itself.
+
+    chunk : Union(int, None)
+        The chunk index of the key, if it uses chunking.
+        Chunk indices start at 1.
+
+    chunksize : Union(int, None)
+        The chunk size for this file, if it uses chunking.
+    """
+
+    def __init__(self, key, remote):
+        self.key = key
+        self.remote = remote
+        try:
+            # name
+            keyparts, self.keyname = key.split('--', 1)
+
+            keyparts = keyparts.split('-')
+
+            # chunking
+            if len(keyparts) > 2 and keyparts[-1].startswith('C') and keyparts[-2].startswith('S'):
+                self.chunk = int(keyparts.pop()[1:])
+                self.chunksize = int(keyparts.pop()[1:])
+            else:
+                self.chunk = None
+                self.chunksize = None
+
+            # mtime
+            if keyparts and keyparts[-1].startswith('m'):
+                self.mtime = int(keyparts.pop()[1:])
+            else:
+                self.mtime = None
+            
+            # filesize
+            if keyparts and keyparts[-1].startswith('s'):
+                self.bytesize = int(keyparts.pop()[1:])
+            else:
+                self.bytesize = None
+
+            # backend
+            self.backend = keyparts.pop()
+        except ValueError:
+            raise RemoteError('bad key: ' + key)
+
+        if len(keyparts):
+            raise RemoteError('bad key: ' + key)
+
+        if self.chunk and self.bytesize:
+            if self.chunk * self.chunksize >= self.bytesize + self.chunksize:
+                raise RemoteError('bad key: ' + key)
+
+    def uris(self, prefix = ''):
+        """
+        The recorded URIs where a key can be downloaded from.
+
+        Parameters
+        ----------
+        prefix : str
+            Only uris that start with the prefix will be returned.
+            The prefix may be empty to get all uris.
+
+        Returns
+        ----------
+        UriList
+            The URIs from which the key can be downloaded.
+        """
+        return UriList(self.key, self.remote.annex, prefix)
+
+    @property
+    def state(self):
+        return self.remote.annex.getstate(self.key)
+
+    @state.setter
+    def state(self, value):
+        self.remote.annex.setstate(self.key, value)
+
+    @property
+    def size(self):
+        if not hasattr(self, '_size'):
+            if self.chunksize:
+                if self.bytesize:
+                    # if this is the last chunk, the size may be truncated
+                    if self.chunk * self.chunksize > self.bytesize:
+                        self._size = self.bytesize % self.chunksize
+                    else:
+                        self._size = self.chunksize
+                else:
+                    # can't tell whether the size is truncated without the full size
+                    self._size = None
+            else:
+                self._size = self.bytesize
+        return self._size
+        
+    def __str__(self):
+        return self.key
+
+    def __repr__(self):
+        return str(self)
+
+class UriList(collections.MutableSet):
+    """
+    A list of URIs.
+
+    This is a MutableSet of str which updates git-annex when mutated with add() or discard().
+
+    Additionally may be indexed in the order git-annex returns the values.
+    """
+
+    def __init__(self, key, annex, prefix = ''):
+        self._key = key
+        self._annex = annex
+        self._prefix = prefix
+        self._uris = None
+
+    @property
+    def uris(self):
+        if self._uris is None:
+            self._uris = self._annex.geturls(self._key, self._prefix)
+        return self._uris
+
+    @classmethod
+    def _from_iterable(cls, iterable):
+        return set(iterable)
+
+    def __contains__(self, uri):
+        return uri in self.uris
+
+    def __iter__(self):
+        return iter(self.uris)
+
+    def __len__(self):
+        return len(self.uris)
+
+    def __getitem__(self, idx):
+        return self.uris[idx]
+
+    def add(self, uri):
+        if uri.split('://')[0].lower() in UriList.URL_SCHEMAS:
+            self._annex.seturlpresent(self._key, uri)
+        else:
+            self._annex.seturipresent(self._key, uri)
+        self._uris = None
+
+    def discard(self, uri):
+        if uri.split('://')[0].lower() in UriList.URL_SCHEMAS:
+            self._annex.seturlmissing(self._key, uri)
+        else:
+            self._annex.seturimissing(self._key, uri)
+        self._uris = None
+
+    URL_SCHEMAS = set(('http', 'ftp', 'gopher', 'mailto', 'mid', 'cid', 'news', 'nntp', 'propsero', 'telnet', 'rlogin', 'tn3270', 'wais'))