A table unit (30) for a walker (2), the walker (2) including a first horizontal rail (21) and a second horizontal rail (22) substantially parallel to the first horizontal rail (21). The table unit (30) has a weight and includes a table portion (35) defining a table area (38) and a first contacting arrangement (31) for contacting the first rail (21) so as to limit movement of the table unit (30) away from the second rail (22) and a second contacting arrangement (32) for contacting the second rail (22) so as to limit movement of the table unit away from the first rail (21). The first contacting arrangement (31) and the second contacting arrangement (32) are shaped to enable the table unit (30) to be mounted on the walker (2) by contacting the first contacting arrangement (31) against the first rail (21) and pivoting the table unit (30) about the first rail (31) to contact the second contacting arrangement (32) against the second rail (22) such that at least some of the weight of the table unit (30) bears down on the second rail (22).
