Filter by Product Type in Views

I am needing to filter by product type in views, but as far as I can see this option isnt available. I tried creating a module to do this but so far no luck. The module was named grid_pricing.module (I'm not sure if the name of the module matters).

function grid_pricing_views_tables() {
  $tables['users'] = array(
    'name' => 'ec_product',
    'filters' => array(
      'ptype' => array(
        'name' => t('Product: Type'),
        'operator' => 'views_handler_operator_or',
        'list' => 'grid_pricing_handler_filter_type',
        'value-type' => 'array',
        'help' => t('This allows you to filter by product type.'),
      ),
    )
  );
  return $tables;
}

function grid_pricing_handler_filter_type($op, $filterinfo) {
  $ptypes = array();
  $result = db_query("SELECT DISTINCT p.ptype FROM {ec_product} p ");
  while ($obj = db_fetch_object($result)) {
    $ptypes[$obj->ptype] = $obj->ptype;
  }
  return $ptypes;
}